Q: What's bimetallic Screw?

A: Bimetallic screw means Bi-Metal screw, which screw is composed of 2 different metals, the base material with normal steel, and the wearing surface flight with higher strength alloy welded, which can be done by manuel welded, PTA welded or HVOF welded

Q: Difference between PTA & HVOF?

A: Varies in much area

- PTA is plasma argon arc welding, HVOF is high velocity oxyfuel spraying

- PTA is on screw flight top area only, while HVOF is on screw full surface

- Alloy used is different, PTA normally used is ni-based alloy with max.15% tungsten, while HVOF is tungsten-based alloy (tungsten above 80%)

Q: How is performance of both

A: PTA bimetallic screw offer acceptable wear resistance with more reasonable price, HVOF offer full surface protection to abrasion & corrosion with accordingly higher cost.

Q: How to choose

A: There is no absolute answer which one is best or not, meet your demand is the best for your choice, if you can't decide, leave it to our engineer