Minimun Hardness T-91
Minimun Hardness T-91
(OP)
My problem is opposite to the raised one for bob74r. For specification of the client the minimum hardness required after PWHT is 200HBN, nevertheless the values are around 170HBN for welds of T-91 (P5B, now P15 E). In no specification I find (including ASTM) minimun values of hardness after PWHT for this material.
Some suggestion? Thank you
Some suggestion? Thank you





RE: Minimun Hardness T-91
RE: Minimun Hardness T-91
I would review your postweld heat treat charts first to verify correct PWHT, and pay particular attention to your ramp rates.
I will say though, that every single P/T91 weld on our current projects that were in the 170/180 BHN range for initial hardness testing came back over 200 BHN after additional surface preparation and a second reading from the telebrineller. Inadequate cleaning of the scale and removal of the decarburized surface can lead to consistently low Brinell values.
RE: Minimun Hardness T-91
RE: Minimun Hardness T-91
RE: Minimun Hardness T-91
We have found the MIC 20 hardness tester (in proper working order) most effective for tube welds. As metengr states, proper surface preparation is imperative.
RE: Minimun Hardness T-91
RE: Minimun Hardness T-91