Frequently Asked Questions

Standard nitriding grade is 38CrMoAlA, with 42CrMo, 34CrAlNi7 and 31CrMoV9 available for high-torque or high-pressure duty, SKD61 for specific extrusion work, and stainless grades where corrosion rather than wear is the enemy. Tell us your process and we will recommend the base steel as well as the surface treatment.

It depends on your filler. For unfilled commodity resins (PE, PP, PS, ABS) a gas-nitrided set is the economical choice. Once you run glass fibre, mineral filler, flame retardant, PVC or high recycled content, a bimetallic lining pays for itself — a set that lasts three to five times longer costs far less per running hour, even though it costs more to buy.

Gas-nitrided layers reach HV 900–1020 at 0.5–0.8 mm case depth. Centrifugally cast bimetallic linings reach HRC 55–72 through a 2–5 mm metallurgically bonded alloy layer. The exact figure depends on the alloy we select for your duty, and it is written on your quotation rather than left open.

Yes. Every order can ship with the mill test certificate for the base steel, the certificate for the alloy powder used in the lining, and NDT results for the bimetallic bond. Ask for them when you enquire — a supplier who hesitates on this question is telling you something.

We can work to a specified alloy grade or recommend an equivalent based on your wear mechanism. Note that the same brand name performs differently between factories because welding parameters change the deposited metallurgy, so we prefer to discuss the duty rather than only the trade name.

Typically 25–40 days after drawing confirmation, depending on diameter, length and heat treatment. Larger diameters and bimetallic linings take longer because a cast liner must be stress-relieved and machined after lining, not before.

Yes. Tell us the situation and we will tell you honestly what is achievable and what is not, before you commit. Our own nitriding and casting furnaces are the reason we can compress schedules — we are not queueing at someone else's heat-treatment shop.

Rust-proofed, oil-sealed and end-capped, then chocked and strapped inside a fumigated wooden case built for the part's weight. We send packing photographs and the packing list before dispatch so you can reconcile on arrival.

We export from Qingdao and Shanghai, and can work FOB, CFR, CIF, EXW or door-delivery depending on your forwarding arrangement. Having our own export documentation means we are not asking a third party to ship for us.

Our machining capability runs to Ø300 mm. That covers almost all injection and extrusion screw barrels in service. If your requirement sits outside our range we will say so in the first reply instead of quoting and struggling later.

We are the factory. Henan Xiwang Machinery Equipment Co., Ltd. operates its own 14,000 m² plant in Jiaozuo with 70–80 staff, four nitriding furnaces and four bimetallic furnaces, and we export directly. Ask for a live walkthrough and judge for yourself.

A screw barrel is built to a drawing, not pulled from a shelf, so a generic price list would mislead you rather than help you. What we can promise is a detailed quotation within 24 hours of receiving your machine model, diameter and material — free, and with no obligation.

Because replacement parts are our whole business, not a spare-parts department. You get faster response, material upgrades the original builder may not offer, and geometry tuned to the material you actually run today rather than the one the machine was sold for. If your machine is still under warranty, we will tell you so and suggest you check the terms first.