Backing Steels for WEXCO Bimetallic Barrels (Cylinders)

The right choice of steel (a.k.a. "backing material") is a prerequisite for a high-performance plasticating barrel (cylinder). While we have made special barrels using a variety of steel types, including 316 and 304 Stainless Steel and AISI 1020 (for liners), and have routinely added Inconel 625 steel to protect cylinder ends and flanges from corrosion, the two most frequently chosen steels are type AISI 4140 and our own WEXCO Type JP38^®. Among those two, our customers prefer "WEXCO JP38^® steel because of its superior performance attributes.

Below are brief descriptions of steel types commonly used by WEXCO.

AISI 4140 Backing Steel

This type of steel is available for barrel diameters that are outside the standard size range of WEXCO JP38^® steels (i.e. barrels with outside diameters of less than 3.5" or larger than 11.5"). However, customers may specify AISI 4140 backing steel for any size barrel.

WEXCO JP-38^® Backing Steel

In 1995, WEXCO Corporation first offered JP-38^®, a higher strength backing material for plasticating barrels. WEXCO JP38^® steel offers a significant strength improvement over AISI 4140 steel. This improved strength technology allows WEXCO to manufacture injection cylinders as a one-piece construction, eliminating the need for expensive heat-treated high pressure sleeves. 

The performance difference between AISI 4140 steel and WEXCO JP38® steel is substantial! The claim for better performance of JP38 as a cylinder backing steel, first verified by WEXCO through testing, has been fully confirmed through actual use of JP38 barrels by processors over more than ten years!

The alloying elements in WEXCO JP38^® steel produce a backing tube with minimal internal stresses. The finished WEXCO JP38^® barrel remains straight even when exposed to the extreme thermal conditions encountered in the molding process. Currently WEXCO JP38^® Backing Steel is available for barrels with 3.5” to 11.5” outside diameter (about 90 - 292 mm).

AISI 316 Stainless  Backing Steel (also AISI 304 Stainless on request)

WEXCO produces extruder barrels made with various types of stainless steel for food processing and other special applications.

Inconel 625 and 718 Backing Steels

To protect against corrosion any exposed areas in the plasticating barrels that are not protected by our corrosion-resistant inlay, we can add Inconel 625 cladding.

For metal-molding applications (e.g. magnesium, etc ), which usually are proprietary processes, we make barrel assemblies with Inconel 718 backing material and special bore protection materials. 

AISI 1020 (series) steel tubes for cylinder "relining"

Our bimetallic liners for barrel relining purposes are typically made from AISI 1020 steel tubes. We supply such bimetallic liners to most "Cylinder Repair & Relining Services" located here in the U.S.A., as well as to several located overseas.

Call us to discuss the best-suited barrel backing steel for your specific application!

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