PTAW : Hard-Facing Overlay? or Hard-Facing Spray Fuse?

[TOVmania]

Dear All,

I am quite confused with the category for PTAW in ASME Section IX QW-257.1. I submitted the question to ASME to get an answer.

In the mean time, an ASME welding inspector insists that it is Spray Fuse because of Plasma Arc form as written in QW-216.3.

Does anyone have an answer for this?

 

[pradipgoswami]

This technique(PTAW) is a popular choice amongst valve manufacturers to deposit hard facing alloys on valve seats, e.g. Stellite deposition. Sec IX lists this under spray-fuse category. The definition is :spray‐fuse: a thermal spraying technique in which the deposit is reheated to fuse the particles and form a metallurgical
bond with the substrate.

PQR requirements are described under:QW-216 HARD-FACING WELD METAL OVERLAY, Clause QW-216.3 to be precise.
As regarding the list of variables , look under table QW-257.1, Heading:Hard‐Facing Spray Fuse(HFSF) (QW-216).

Hope it would help you.

Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist
Ontario,Canada.
ca.linkedin.com/pub/pradip-goswami/5/985/299

 

[TOVmania]

Dear Pradip,

Thank you for your clarification. Then how is the fusing temperature and cooling rate measured/determined? Is is based on the melting temperature of the substrate and the fusing material?

 

[metengr]

Suggest you review the information below

http://cdn.intechopen.com/pdfs/25058.pdf

 

[TOVmania]

We received confirmation from the ASME Inspector that PTAW(or PTA) is determined HFO not HFSF.