What are Stainless Steel Pipes?

One of the most supplied in Chuan Kok’s product range is stainless steel pipes. Stainless steel pipes are consumed in high performance fluid or gas line application. Most clients requests for seamless stainless steel pipes due to their corrosion resistance and ability to withstand pressure.

Figure 1: Stainless Steel Pipe Specification


Chuan Kok keep stock for seamless stainless steel pipes in dual grade SS316/SS316L. The stainless steel pipes are in accordance to ASTM A312. ASTM A312 is the standard specification for seamless, welded, and heavily cold worked austenitic stainless steel pipe.

Stainless Steel Pipe Attributes:

The minimum tensile strength for stainless steel pipes is 515 N/mm² while minimum yield strength at Rp 0.2% at 205 N/mm². Stainless steel pipes contain at least 10.5% of chromium. This allows it to form an invisible chrome-oxide layer by reaction with oxygen.

SS316/316L is a chromium-nickel-molybdenum bearing austenitic stainless steel. The molybdenum content in stainless steel pipe is around 2.0% to 3.0%, while nickel content is around 11% to 14%.  The nickel and molybdenum content provides great corrosion resistance in corrosive surroundings, such as salt water or chloride environments. In addition, SS316/316L material will reduce the tendency of the material to crack after welding. It also provides higher tensile strength at elevated temperature.

The meaning of “L” designation in SS316L grade is that carbon content is restricted to 0.03% where the normal carbon content in stainless steel SS316 is 0.08%. The lesser the carbon content the stainless steel has, the greater it is in weldability. And it also prevents chromium from being depleted, thus, it can still form the chrome oxide layer on the pipe surface.

Stainless Steel Pipe Finishing:

Pipes are supplied in 1 type of finishing which is Annealed and Pickled. Annealing is a heat treatment that alters the physical and chemical properties of the material. It also increases the ductility and reduces the stainless steel pipe hardness. Pickling is a metal surface treatment that contains acid to remove the impurities on the pipe surface.

Figure 2: Annealed & Pickled Stainless Steel Pipe

Stainless Steel Pipe’s Pipe Ends:

 There are 3 main types of pipe ends for stainless steel pipe, namely plain end (PE), bevel end (BE) and threaded end (TE).

Plain end pipes are pipes that with unfinished ends. Generally, plain end pipes are used for small diameters pipe systems. It also suitable for socket weld fittings and flanges.

Bevel end pipes are pipes that have a standard angle of 30° (+5°/-0°) on the pipes end surface. It also has a root face of 1.6mm (±0.8mm). However, pipes with non-standard angles can also be produced. Bevel end pipes are usually used for butt weld fittings and flanges where they can be directly welded to each other. Picture of bevel end are illustrate as below.


Threaded end pipes are pipes that with tapered groove that cuts into the ends of pipes. The tapered groove allows the pipes to be easily assembled with threaded fittings. The standard thread for tapered groove is National Pipe Thread (NPT). As NPT connections are assembled, it will reduce the possibility of leakage.

Outer Diameter and Wall Thickness Specifications:

Pipes outer diameter (OD) is in accordance to ASTM A312. The tolerance of pipe outer diameter and wall thickness are as below:

Untitled 2

From table above, for pipes OD that range from 1/8″NB – 1 1/2″NB, the standard OD tolerance is +0.4mm, -0.8mm. For Chuan Kok’s pipe sizes 1/8″NB – 1 1/2″NB, we control the OD tolerance to be ±0.4mm. For 2″NB – 4″NB, the standard OD tolerance is ±0.8mm to which our pipes comply. For 5″NB – 8″NB pipes, the standard OD tolerance is +1.6mm, -0.8mm.

For pipes wall thickness, the specifications are +/- 12.5%. However, we regulate the wall thickness to  +/- 10%.

Stainless Steel Pipe Wall Thickness:

Figure 3: Stainless Steel Pipe “SCH’ thickness

Wall thickness of stainless steel pipe is expressed in “schedules”, abbreviated as SCH. Thickness of stainless steel pipes can be divided to several groups such as SCH10S, SCH40S, SCH80S, SCH160S and SCHXXS. These represent different kind of thickness which depends on the pipe’s outer diameter (OD).

Please refer below table for stainless steel pipes wall thickness.

Untitled t

Stainless Steel Pipes Manufacturing Process

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Chuan Kok Hardware maintains a large stock of stainless steel pipe to be needed in high performance hydraulic line application. Seamless cold drawn tubes are being constantly offered to clients due to its quality and cleanliness. Seamless cold drawn pipes are precision in dimension and free of scale. To find out more about Stainless Steel Pipes, do visit us at www.chuankok.com/stainless-steel-pipes.html

What are Stainless Steel Tubes?

Stainless steel tubes are usually made in accordance to ASTM A269/A213. ASTM A269 is the standard specification for seamless and welded austenitic stainless steel tubing for general service. While for ASTM A213, it is a standard specification for seamless ferritic and austenitic alloy-steel boiler, super heater and heat-exchanger tubes. They are also commonly made to dual grade which is SS316/316L with seamless quality.

Figure 1: Stainless Steel Tube Bundle

Stainless Steel Tube Attributes:
The minimum yield strength for stainless steel tube is 515 N/mm² and with maximum 90 HRB of hardness. Maximum 80 HRB is specified so that compression fittings can work well with the tubes. Stainless steel tubes contain at least 10.5% of chromium and it will react with the oxygen to form an invisible chrome-oxide layer. The layer is strong enough to prevent further oxygen from rusting the surface.

SS316/316L is molybdenum-bearing austenitic stainless steel with molybdenum content ranging from 2.0 to 3.0%. The high nickel and molybdenum content provides resistance in highly corrosive surroundings such as salt water or chloride environments. In addition, SS316/316L also provides excellent elevated temperature tensile, outstanding formability and weld-ability.

Figure 2: Stainless Steel Tube Bundle

The means of “L” designation after the grade number is the carbon content is restricted to a maximum of 0.03% where the normal level of carbon content of stainless steel are maximum of 0.08%. The lower level of carbon content stainless steel tubes are used where welding will be performed. This lower level carbon content prevents the chromium from being depleted and thus it can still form the chrome-oxide layer on the tube surface.

Stainless Steel Tube Finishing:
Tubes are supplied in 3 type of finishing as Annealed and Pickled, Polished 320 Grit, and Bright Annealed.

Figure 3: Annealed & Pickled Tube(Top), Polished 320 Grit Tube (Bottom)

Usually stainless steel tubes are supply in anneal and pickle condition. Anneal is a heat treatment that will alter the physical and chemical properties of the material. It increases the ductility and reduces the hardness of stainless steel tube. Pickling is a metal surface treatment that contains strong acid to remove the impurities on the tube surface.

Polished 320 Grit are produced for applications where a smoother finishing is required for aesthetic application. Bright Annealed is produced by heat treating (annealing) steel with a controlled atmosphere. After the heat treatment, the steel has reflective, mirror-like appearance.

Stainless Steel Tubes are also suitable for flaring and cold bending. For cold bending, a bend radius of 3x the external tube diameter is recommended with tube benders or by hand. Tubes made of SS316/316L are suitable for arc welding according to usual techniques. The welding filler should be selected in accordance with DIN EN 1600 and DIN EN 12072 part 1 taking into account the type of application and the welding technique.

Outer Diameter and Tube Thickness Specifications:
The tubes outer diameter (OD) are according to ASTM A269/A213. However, for hydraulic applications, a tighter tolerance is usually specified to work well with compression fittings. Tolerance specifications are as per below:


For tubes thickness, A269 and A213 has 2 different type of wall thickness tolerance. For ASTM A269, the permissible variations in wall thickness is +/− 10%. However for ASTM A213, there are 2 options for the wall thickness tolerance. The 1st option is minimum wall thickness which is + 20%, − 0% of wall thickness. The 2nd option is average wall thickness which is +/− 10% of wall thickness.

Our usual option for tubing products wall thickness of tubing are +/− 10% and it will comply to both A269 and A213 standards.

Stainless steel tubes manufacturing process is illustrated below.

Manufacturing Process:


Chuan Kok Hardware maintains a large stock of stainless steel tube to be needed in high performance hydraulic line application. Seamless cold drawn tubes are being constantly offered to clients due to its quality and cleanliness. Seamless cold drawn tubes are precision in dimension and free of scale.

To find out more about stainless steel tubes, please watch the video below:

For more information, please visit our site at www.chuankok.com/stainless-steel-tubes.html

5 Little Known Facts About Stainless Steel

What is Stainless Steel:

Figure 1: Stainless Steel Round Bars

You may be seeing stainless steel everywhere around you, and you began to wonder what makes this material so unique that you seem to find it, not only in construction sites, pipes and even in your kitchen! Let’s take a closer look at these stainless steel facts – some, you may even find surprising.

Stainless steel’s magnetic properties:
You may find that some stainless steel are magnetic. Stainless steel is divided into groups and each differs in the composition of alloys and atomic arrangement which causes the variation of the steel’s magnetic properties. Generally, ferritic types are magnetic and austenitic types are usually not.

Stainless steel can stain:

Stainless steel is composed of material that resists corrosion and oxidation, giving it the ability to “self-repair” when exposed to oxygen and moisture, however, its protective oxide film coating wears out over time. This is why, contrary to its name, stainless steel can stain. It is, therefore, important to ensure sufficient oxygen contact and proper handling and maintenance when working with this material.

Figure 2: Stainless Steel Material

Stainless steel can be recycled:

According to American Iron and Steel Institute, 88% of stainless steel gets recycled and every 2 out of 3 tons of newly made steel were made from recycled steel. The same goes with its by-products, like mill scale, processing liquid and steelmaking slags. Steel making sludge and dust are also re-used to create zinc and similar other products.

Stainless steel can be used as “Soap”:

The ability of stainless Steel to neutralize or reduce pungent scents and odors, is the main reason why you find them in your kitchen.  This characteristic is a result of sulfur compounds, binding with various with various elements.

Figure 3: Coiled Stainless Steel Tube

Stainless steel can change size:

Additional fact: Did you know that the Eiffel Tower’s height is approximately 6” shorter during the winter? The Eiffel tower stands at 984 feet tall (minus the antenna) during the summer. This is due to the stainless steel’s reaction to temperature change. It expands and contract as the temperature varies. This is one of the major factors that the construction industry takes note of, before initiating construction using this material.

It is for being low maintenance and the above mentioned unique qualities, that stainless steel material has found its way in different industries. For more information, don’t hesitate to Contact Us at Chuan Kok Hardware & Machinery Pte Ltd.

To find out more about the little known facts of stainless steel, please watch the video below:

What are Pressure Gauges?


Figure 1
Figure 1: Material of pressure gauge casing (stainless steel) and connection (brass)

Pressure gauges are devices used to measure pressures in hydraulic systems and made in accordance to EN 837-1 European standards. It is applicable for hydraulic oil and gaseous media. The reading measurements are shown on the face of the gauge. Measuring pressure on equipment is essential for monitoring and providingthe smooth functioning and operating safety of the system.

Material and size:

A pressure gauge has two parts, the casing and the connection point. Usually, the material for the casing is stainless steel (1.4301) and the material for the bottom or back connection is brass (Figure 1). The lenses are made of acrylic sight glass. The size of the casing is usually available in 63mm (2 1/2 Inches) and 100mm (4 Inches).


Figure 2
Figure 2: Standard dual scales with bar and psi

There are two different connection directions, stem (bottom) mounting and panel (back) mounting. The connection direction is dependent on the system design. Connection wise, 1/4″BSPP & 1/4″NPT are usually used for gauges with size diameter 63mm, while 1/2″BSPP and 1/2″NPT are available for size diameter 100mm.

Reading range:

Pressure gauges come with standard dual scales with pressure indication in kilopascal (bar) and poun ds per square inch (psi) (Figure 2). The gauges are available in different measuring ranges to suit different installation needs.


There are two types of gauges are available; dry dial gauge (Figure 3) and glycerine filled gauge. Glycerine gauges reduce the effects of vibration and oscillation for needle reading accuracy. It also lubricates the movement and internal parts. In general, it improves reliability and extends the life of pressure gauges. Gauges are made to accurately read only the middle values. The accuracy range is ±1.6% of the full-scale for dial size 63mm, and ±1.0% of the full-scale for dial size 100mm. In order to make sure the readings on the gauge are accurate, a calibration test can be done by a laboratory. A certificate of calibration will be issued by a laboratory to confirm that the gauge accuracy. There are also many panel mounting options available for installation of gauges. The options include u-bolt assembly, front flange assembly, rear flange assembly and u-bolt with front flange assembly.

Permissible Temperatures:

Pressure gauges work well within a temperature range of -20°C to +60°C / -4°F to +140°F. Out of this temperature range, the gauge readings will be inaccurate.

Brands and Manufacturers:

A highly recommended manufacturer for gauges is Walter Stauffenberg GmbH & Co. KG. Walter Stauffenberg GmbH & Co. KG is a German manufacturer that has more than 50 years of specialized experience in manufacturing Stauff branded pressure gauge. Other reputable manufacturers include WIKA GmbH from Germany and Parker Hannifin from USA.

Based in Singapore, Chuan Kok Hardware & Machinery Pte Ltd is an international distributor of Pressure Gauges. To find out more about Pressure Gauges, do visit us at www.chuankok.com/stauff-pressure-gauges.html


Stauff Brand

What are SAE Flanges?

What are SAE Flanges? If this question confounds you, this is the right place to get answers.

S/W SAE Flange photo


SAE Flanges is a range of high pressure hydraulic flange which is made in accordance to SAE J518 standards. The acronym SAE stands for Society of Automotive Engineers. These flanges are used on oil hydraulic systems in many fields (shipbuilding, mobile hydraulic equipment, machine tools, earth moving machines, etc… ) and where there is passage of oil under pressure.

Flanges are made from normalized forgings and are usually of two kinds of material, steel ST52.3 and stainless steel AISI SS316L.

SAE Flanges come in two series, SAE code 61 (3000 series) and SAE code 62 (6000 series). For code 61 (3000# series), they are available in all nominal sizes between DN10 (3/8″) and DN125 (5″). For code 62 (6000# series), they are available in all nominal sizes between DN10 (3/8″) and DN80 (3″)

Working Pressure:
The standard pressure ranges from 34 to 345 bar for code 61 (3000 series) and 200 to 414 bar for code 62 (6000 series). Please take note that the pressure information of the flange and connected equipment combinations may vary from each other. For example: if a pipe connected to the flange has a lower working pressure, it will result in an overall lower working pressure of the system. Therefore, please consider the lowest pressure as the maximum working pressure of this combination.

Temperature Range:
The standard working pressure of carbon steel SAE flanges is between -40°C and +120°C. For stainless steel, the standard working pressure is between -60°C and +50°C. Working Pressure for SAE Flanges made from stainless steel and used at elevated temperatures have to be:

Reduced by 4%: +50°C to < +100°C
Reduced by 11%: +100°C to < +200°C
Reduced by 20%: +200°C to < +250°C

How SAE Flanges work:

A complete set comprises of a flat side flange and an o-ring side flange. The o-ring side flange contains a groove seat to place a rubber o-ring (normally made of NBR material). The complete set forms a seal between a flat surface and o-ring held in a recessed circular groove in the other half. Tightening the bolts draws the two halves together and compresses the O-ring.

Due to this usage of the o-ring, flanges with o-rings has an advantage over metal to metal flanges as all-metal flanges are more prone to leakage because they must be tightened to a higher, yet narrower torque range. This makes metal to metal flanges more prone to strip threads or crack.

A complete set of flange is tightened using socket head cap screws & spring washers according to recommended torque. The screw lengths are usually shorter than the overall SAE flanges length but this is normal in accordance to SAE J518 standard. Also, as per SAE J518, there are no requirements for hex nuts for securing the flanges.

Configurations of SAE Flanges:
Commonly used connection types consist of: Weld In/ Socket Weld, Weld On/ Butt Weld, NPT Threaded, BSP Threaded, Blind Flanges, Split Flanges.

Upon request, flanges can be supplied complete with screws, washers and NBR/Viton o-rings.

Oleo Tecnica, SAE Flange manufacturer

Brands of Flanges:
A highly recommended brand for SAE Flanges is Oleo Tecnica. Oleo Tecnica is an Italian manufacturer specializing in SAE Flanges. Oleo Tecnica was established in 1976 and has more than 36 years of specialized experience manufacturing flanges. Other well established brands include Parker Hannifin and Stauff.

To find out more about how to assemble SAE Flanges, please watch:

Based in Singapore, Chuan Kok Hardware & Machinery Pte Ltd is an international distributor of SAE Flanges. To find out more about Oleo Tecnica SAE Flanges, do visit us at www.chuankok.com/sae-flanges.html

What are Square Flanges?

Introduction to Flanges:

A pipe flange is used in the assembly of pipe to pipe or other components like valves, tees, elbows etc. The flanges are bolted together, creating several lengths of pipes or other assemblies. There are many different flange standards to be found worldwide. Common world standards include ASA/ANSI/ASME (USA), PN/DIN (European), BS10 (British/Australian), and JIS/KS (Japanese/Korean). Flanges in each standard are divided into “pressure classes”, allowing flanges to be capable of taking different pressure ratings.

Square Flanges:

Square Flange made in accordance to JIS B2291 standard is a connecting piece that links JIS (Japanese Industrial Standards) nominal bore size pipes together and has a working pressure of up to 210kgf/cm2. This is equivalent to 210 Bar, or 21MPa. They are usually used in high pressure systems such as hydraulic and steam lines for up to 3,000 PSI working pressure.

There are three types of Square Flanges under this standard:

  1. SHAB – Used with hexagon hex bolts, larger flange body size (Figure 1)
  2. SSAB – Used with socket cap screw, smaller flange body size than SHAB (Figure2)
  3. LSA – Oring side only, L shaped internal flow (Figure 3)Untitled

A complete set of square flanges consist of the female flange (oring side), male flange (flat side), oring, and bolts. The female flange is identified as part A. The male flange is identified as part B. And the complete set is AB.

Figure 4 – Left : SHAB Square Flange using Hexagon bolts (larger flange body), Right: SSAB Square Flange using Socket Cap Screw (smaller Flange body)

Blind Flanges:

Another type of flange available are Blind Flanges. These are used to seal the end of a piping system or pressure vessel openings to prevent flow.  Blind pipe flanges are commonly used for pressure testing the flow of liquid or gas through a pipe or vessel.  They also allow easy access to the pipe in the event that work must be done inside the line.  Only one side of a blind flange is used for the termination of the piping system. Either the female blind flange (oring side), or male flange (flat side) will be connected to the component to close off the pipe line  (Figure 5).

Figure 5:  Oring and Flat Square Blind Flanges


Material, Size Range and Connection:

Square Flanges are available in either carbon steel (SF440A) or stainless steel (SS316) material. The size range from 1/4″NB to 6”NB and the connection type is Socket Welding.

Brands of Square Flanges:

A highly recommended manufacturer for square flanges is KPL Industry Co., Ltd. KPL Industry Co., Ltd is a Korean manufacturer that specializes in producing various forged products in the field marine & offshore, seawater desalination plant, nuclear power plant and industrial sites.

To find out more about how to assemble Square Flanges, please watch:


Chuan Kok Hardware & Machinery is a stockist of KPL JIS B2291 Square Flanges in Singapore. To find out more about square flanges do visit us at www.chuankok.com/square-flanges.html

03 KPL

What are Forged Pipe Fittings?


Figure 1 Forged Pipe Fittings
Figure 1: Forged Pipe Fittings


Forged Pipe Fittings (Socket Weld and Threaded) are made in accordance to ASME (American Society of Mechanical Engineers) B16.11, MSS-SP-79\ 83\ 95\97 and BS3799 standards, and are used to connect nominal bore schedule pipes and pipelines. (See Figure 1). The applications range from chemical, petrochemical, power generation and OEM manufacturing industry as well other applications where vibration, high pressure or extremely corrosive conditions exist.


Forged pipe fittings are generally available in two materials: Carbon Steel (ASTM A105 material spec), and Stainless Steel SS316 (ASTM A182 material spec). The surface of carbon steel A105 forged pipe fittings may be further reinforced against corrosion through galvanizing. This is an optional add-on which customers may include at an additional cost.

Pressure Rating and Size Range:

Figure 2 class 3000 vs 6000 fittings
Figure 2: Class 3000 VS 6000 fittings

Fittings come in a variety of classes and material grades for any application. The fittings are available in class 3,000 and 6,000. (See Figure 2). Although class 2,000 and 9,000 fittings exist, these are rarely used and class 3,000 and 6,000 remain the more common class of fittings used. Sizes of forged fittings typically range from 1/8” to 4”. And reducing sizes are available for common parts like couplings, tees, hex bushings and nipples.



Connection Types:

20131018_171135 - Copy
Figure 3:  S/W x S/W x NPT TEE

Class 3,000 and 6,000 forged pipe fittings comes in two types of connection: Socket Weld, or Threaded. NPT (National Pipe Thread) is the most common thread type although BSPP (British Standard Pipe Parallel thread) is also be available for certain parts like Full Couplings, Hex Bushings and Hex Nipples. Socket weld connection is significantly more popular than threaded since most applications call for completely sealing off a line and eliminating all possibility of leakage.

The fittings are normally produced with the same connection for all sides of the same fitting. That means, a socket weld fitting will have socket weld connection on all sides. Should different connection ends be required, additional machining could be possible but at a higher cost and a longer lead time. i.e. Socket weld x Socket weld x NPT Tee . (See Figure 3)

Brands of Forged Fittings:

A highly recommended manufacturer for forged fittings is Both-Well Steel Fittings Co., Ltd. Both-Well Steel Fittings Co., Ltd was established in 1985 in Taiwan, and has been well-recognized among customers worldwide for excellence in its quality and services. Both-Well Quality Management System has been cerified with ISO 9001:2000, PED, together with all major international-recognized certificates and also being listed on the Approval Supplier List of major domestic refineries, petro-chemical factories in Taiwan.

Chuan Kok Hardware & Machinery is a stockist of Both-Well and LAME High Pressure Forged Fittings in Singapore. To find out more about forged pipe fittings, do visit us at www.chuankok.com/pipe-fittings.html




Introduction to Pipe Clamps


Pipe Clamp Edited
Pipe clamp shell body

Pipe clamps made in accordance to DIN 3015 standards are devices used to grip and support mechanical or structural parts. They are usually used for pipe and hose installations in applications such as hydraulics, power plant piping, fuel power, general industrial pipe construction, nuclear reactor construction, instrumentation and control technology and pneumatics. The key purpose of using the clamps is to reduce vibration and noise.Pipe clamps usually consist of four components and they are the clamp shell body, cover plate, single weld plate and hexagon head bolts.

There are also a variety of other accessories available for pipe clamps. For example, the elongated weld plates, stacking bolts, mounting rails and rail nuts. These are used for different installation methods of the pipe clamps.

Material Pipe Clamp Edited
Material of pipe clamp


The materials that are normally used to make the clamp body are polypropylene   (PP), polyamide (PA) and aluminium (AL). Generally, polypropylene is green, polyamide is black, and aluminium is silver in color. The different colors help to differentiate the material that is being used. The clamp body however, can also be made in other materials upon request. As for the cover plate, single weld plate and hexagon head bolts; they are usually in either steel or stainless steel.

Series Edited
Series of pipe clamp


Pipe clamps come in three series and each has its own usage. Standard series which are made in accordance to DIN 3015 Part 1 are meant for light duty usage. Heavy series which are made in accordance to DIN 3015 Part 2 are meant for heavy duty usage. Last but not least, the twin series, which are made in accordance to DIN 3015 Part 3 are meant for light duty usage and space saving.

Range of sizes:

The size of a clamp varies according to the type of series. For standard series, the size ranges from 6mm to 102mm. For heavy series, the size ranges from 6mm to 406mm. Lastly, for twin series, the size ranges from 6mm to 42mm. When deciding which clamp series is appropriate for use, we have to first measure the external diameter of the pipe, tube or hose we are intending to have the clamp installed onto. The reading measurements for these are usually in metric sizes and the outer diameter size or nominal bore sizes are in inches. With the measurements of the pipe, tube or hose, an appropriate clamp series can then be recommended.

Installation of Pipe Clamps:

A common way of installing the clamps involves welding the weld plate or mounting rails to the floors, walls or ceilings. There are also other ways of securing the clamps without welding. An example is to use an elongated weld plate with bolts to secure the clamps.

Accessories of pipe clamp Edited
Accessories of pipe clamp

Some common types of assemblies used with the clamp shell body are as follow.

· Cover plate, hexagon head bolts and single weld plate

· Cover plate, hexagon head bolts and elongated weld plate

· Cover plate, hexagon head bolts and hexagon rail nuts

· Cover plate, safety locking plate and stacking bolts

· Single weld plate and socket cap screws

STAUFF, Pipe Clamp manufacturer

Brands of Pipe Clamps:

A highly recommended manufacturer for clamps is Walter Stauffenberg GmbH & Co. KG. Walter Stauffenberg GmbH & Co. KG is a German manufacturer that has more than 50 years of specialized experience in manufacturing Stauff branded pipe clamps. Other reputable manufacturers for clamps include FKB GmbH & Pi.Effe.Ci.

Based in Singapore, Chuan Kok Hardware & Machinery Pte Ltd is an international distributor of Pipe Clamp. To find out more about Pipe Clamp, do visit us at www.chuankok.com/pipe-clamps.html


Introduction to JIC Fittings

JIC Components: Fitting, Flare Nut & Sleeve
Figure 1: JIC Components: Fitting, Flare Nut & Sleeve

JIC Fitting is a range of hydraulic fittings which is made in accordance to the SAE J514 standards. The acronym JIC stands for Joint Industry Council. It is also known as the JIC 37 degrees flare fitting because it has a 37 degrees flare seating surface. These fittings are used on oil hydraulic systems in many fields (fuel delivery, fuel power application, shipbuilding, mobile hydraulic equipment, etc…). A JIC fitting system has three components that make a tubing assembly: fitting, flare nut, and sleeve (Figure 1).

SS316 JIC Fittings
Figure 2: SS316 JIC Fitting

Materials used to fabricate JIC fittings include carbon steel and stainless steel SS316L.

JIC body and flare nut are available in outer diameter (“OD) sizes between 1/8” to 1 1/2”. Sleeve has two different reading measurements, metric size (mm) and inch outer diameter (“OD). Sleeve size is available from 3mm to 50mm and 1/8” to 2”. Fitting sizes are designated by the corresponding outside diameter of the tubing for the various types of tube ends.

Working Pressure:
The standard working pressure of the fittings ranges from 1000 to 5000 psi for different sizes and connections. The minimum burst pressure is four times the working pressure. JIC fittings must be able to withstand twice the working pressure for a period of 1 minute without failure or leakage.

Please take note that the pressure rating of a same fitting may vary when it is connected to different equipments. For example, if a fitting with a low working pressure is connected to a pipe, it will result in an overall even lower working pressure. In all cases, always consider the lowest pressure as the maximum working pressure of the system.

Connection tube and fitting
Connection tube and JIC fitting

How does a JIC fitting works:
For tube connections, the assembly procedure starts from the preparation of the tube. First, the nut and sleeve are inserted onto the end of a tube. With the use of a flaring tool, form the end of the tube to 37 degrees. Next, tighten the nut by using a spanner until the nut is tight and the sleeve grips onto the tube. If the fittings are bench assembled, the gripping action can be determined by rotating the tube by hand as the nut is drawn down. When the tube can no longer be rotated by hand, the sleeve has gripped onto the tube. When this happens, tighten the nut by turning it one full turn. This may vary slightly with different tubing materials, but for general practice, it is a good rule to follow.

Configurations of JIC Fitting:
Commonly used connection types consist of: JIC/BSPP Male Connector, JIC/ NPT Male connector, JIC Union, JIC/NPT Swivel Male Connector, JIC/BSPP Swivel Male Connector.

hs corporation
Hyupshin, JIC Fitting manufacturer

HS Corporation:
HS Corporation is a Korean manufacturer specializing in JIC Fitting. Established in 1980, HS Corporation has more than 30 years of specialized experience in manufacturing fittings. HS Corporation JIC Fittings are distributed by Chuan Kok Hardware & Machinery Pte Ltd to major shipyards, engineering as well as marine and offshore companies in Singapore.

Based in Singapore, Chuan Kok Hardware & Machinery Pte Ltd is an international distributor of JIC Fittings. To find out more about JIC Fittings, do visit us at www.chuankok.com/jic-fittings.html

What is a Walform machine?


What is a walform machine?

Walform Machine
Figure 1: Walform Machine

Walform machine is a portable tube reshaping machine used in a walform plus tube fitting system that produces high quality tube connections.

What is DIN 2353 and what are the applications of these tube fittings?

DIN 2353 fittings are a range of metric tube fittings made in accordance to ISO 8434-1 standards. They are also known as “Compression-Joint”, or “Bite-Type” fittings as the profile ring in the fitting “bites” onto the tube to create the connection. These fittings are used to connect hydraulic tubes together to form a hydraulic line that allows fluid to flow through at high pressures. A simple hydraulic line in a vessel or an oil rig can easily comprises of up to hundreds & thousands of DIN 2353 fittings.

What is the current process for conventional tube fittings and what are the risks involved?

Figure 2: How compression works

Under the conventional method of connecting tubes using DIN 2353 fittings, the profile ring cuts into the surface of the tube and reshapes it when the nut is tightened. This in turns create a groove for the fitting to grip onto the tube. (Figure 2) There are two points to note here. Firstly, this procedure can only be performed by trained workmen who have undergone a course on assembly and alignment of DIN 2353 fittings. Secondly, it is more suitable for low volume production, repair works, and in environments whereby there is no power supply being made available. Having said so, there are still risks involved because the process is prone to human errors. During the tightening process, the workmen can over or under tighten the nuts and when this happens, it can lead to leakages which can pose serious dangers under high pressure. Leakages can lead to slip and fall hazards, fire danger, as well as contamination of the environment. Even a pinhole leak can release hydraulic fluid that is enough to penetrate both clothing and skin.The danger it can bring is definitely life threatening.

What are the benefits of replacing the current process with walform machine?

With the use of a walform machine, the tubes get reshaped by simply inserting the tube into the configured walform machine, creating a profile ring in the tube itself. A viton seal acts as the leakage block and tubes can be connected easily just by tightening the nut. With these in place, there is consistency and quality control over all the tubes, making them more reliable and safer than before. The risks that stem from improper assembly of the tubes as mentioned earlier can be reduced dramatically, creating a safer working environment.

Businesses can also save on manpower costs with the use of walform machines since it only requires one man to operate one machine. Lesser time is also required to configure a tube and this means that businesses can now handle larger volumes instead of being restricted by the use of the conventional method.

On top of all these, the assembly using a walform machine can be repeated multiple times and yet remain intact unlike the conventional method whereby the tube fittings can be damaged by over tightening. This reduces wastage as well as costs of replacing the tube fittings that are damaged in the process.

Furthermore, the use of the walform machine is simple and can be carried out by anyone; businesses need not send their workmen for such training in the future. This reduces the costs of business.

How does the equipment increase or enhance productivity of the business (for example in terms of reduced man-hours, more output or improved work processes)?

The process of reshaping a tube is made simpler with the shift from manual method to partial machine method. The only thing the workmen need to do is to insert the tube into the configured walform machine.

With the risks of leakages being reduced by the use of a walform machine, the performance efficiency can be improved which in turn improves the overall effectiveness of the equipment. This is because in hydraulic machinery, the primary cause of reduced performance efficiency is often caused by internal or external fluid leakages. Businesses can also avoid purchasing new equipments and tubes prematurely. The life cycle of the equipment and tubes can be extended significantly hence, reducing unnecessary expenses.

The time required to reshape a tube using the walform machine is 5 to 8 seconds versus the manual method at approximately 1 minute. Businesses save approximately 52 seconds to 55 seconds for each tube connection and this transform to 6 to 11 more tube connections than the manual method for each minute. Thus, the overall productivity and output increases.

Last but not least, businesses do not need as many workmen since only one man is required to operate one machine. Given that more tubes can be produced with lesser manpower, man-hours is reduced substantially too.


Based in Singapore, Chuan Kok Hardware & Machinery Pte Ltd is an international distributor of Walform machine and Walform seals. To find out more about Walform machine and Walform seals, do visit us at www.chuankok.com/eaton+Walform.html