Qualifying a WPS joining 4130 to P1, Gr. 2 with impact testing

[newweldeng09]

I am joining 4130 to a P1, Gr. 2 carbon steel. Impact testing is required. The 4130 base metal was impact tested to meet 37/25 ft-lbs. The carbon steel was impact tested to meet 18/12 ft-lbs. Why do I have to impact test the 4130 HAZ to meet 37/25 ft-lbs. and the carbon steel HAZ to meet 18/12 ft-lbs. as required by UG-84(g)(5)? Why can't I qualify the procedure using the lower energy requirement as a minimum?

 

[metengr]

4130 is not recognized by ASME Section VIII, Div 1 for pressure retaining material and impact testing. Second, UG-84 (g) and subsequent subparagraphs under (g) apply to weld metal impact testing only and comparison with base metal. Are you planning to test the weld metal used to join a non-code approved material???

 

[newweldeng09]

I know that 4130 is not Code approved. So based on your statement above I cannot apply impact testing requirements of the Code to this material, correct?

For my general knowledge, if I am qualifying two dissimilar Code approved metals that are in Table UCS-23 and impact testing is required, do I have to meet the minimum toughness requirements specified in Fig. UG-84.1 for each base metal or for the base metal that has the lower impact toughness requirements for each HAZ?

I was planning on testing the weld metal used to join the materials together. I was going to weld it with GTAW and FCAW with ER70S-3 and E71T-12MJ. The impact test requirement for the weld metal is 18/12 based on the minimum requirement for the carbon steel. (This application is for a 4130 nozzle to a P1 case weldment per API 617. The customer gave us approval to use the 4130 material).

 

[metengr]

First, ASME Section VIII, Div 1 rules can be applied to materials or components which will not be code stamped. My point was more of interest in your citing rules from Section VIII on material and trying to take exemptions that cannot be used because 4130 has no minimum impact values or MDMT versus thickness curve.

Second, have you read through UG-84 and other Parts - UCS to understand the rationale for impact testing of base materials and weld metal? Either you follow the rules completely for impact testing of both base materials and weld metal or develop your own requirements because you can't take credit for impact exemptions for non-code approved base material.

For your WPS qualification, you need to test the P1 and 4130 base material combination, HAZ and weld metal to ensure compliance with your minimum impact requirements.