Low Alloy Electrodes 1

[bmoorthy]

Back ground
Carbon Steel component (Say API 5L x 65 Pipe welded pipe, thickness 15mm) is being welded with Electrodes and the electrodes are classified under Low alloy electrodes (As per AWS/ ASME Sec II C).

I know that (On general situation) that when a low alloy base metal is welded, PWHT is called for.

What if CS material is welded with Low alloy electrode. Does it call for PWHT.

 

[metengr]

PWHT requirements for ASME Codes and Standards applications were developed based on chemical composition of the base materials that are joined. The concern is residual stress and toughness requirements, after welding, for either base material. The weld deposit by design is to have higher strength in comparison to either base material being joined. Ductility of the weld deposit and base metal HAZ is demonstrated thru bend testing during qualification of the weld procedure.

 

[metengr]

One additional comment, is that B31.3 Power Piping Code in Section 331 Heat Treatment provides guidance in Table 333.1.1 on post weld heat treatment requirements based on base metal(s) being joined (P-No) and weld metal analysis A-number. I don't believe B31.1 has this added information. I would suggest you review B31.3 Section 331.

 

[stanweld]

Since you are welding X-65 pipeline type materials, you may be welding with E8010-G or E9010-G electrodes. Preheat is recommended when using these electrodes, especially during welding the root and hot passes. PWHT is normally not performed nor required.

When welding X-65 with low hydrogen electrodes similar to E8018-C3 or E9018M Nickel/Chrome/Mo type alloy electrodes, preheat is normally not required and PWHT is normally not performed.