My line of thinking is similar to RS, but I would be more concerned if the welder is spraying the water on the weld and adjacent base metal while the temperature is above 1330 degrees F. If the carbon steel is above the magic temperature of 1330 F, the steel is above the lower temperature of transformation. In other words, it may be partially austenized and it can be quenched to form a hard brittle microstructure. The carbon content and the sum effects of other alloying constituents will determine just how hard the weld and HAZ can be.
If the weld and adjacent base metal had cooled to a temperature below 1330, I would be less concerned. It is still an issue to be addressed because the welder should not be hastening the cooling rates without proper direction from management, preferably someone with a good understanding of how metals respond to heat treatment. If assisted cooling is required, it should be addressed by the WPS and not instituted by the welder.
Best regards – Al
I agree with Al and all about the lower transformation temp. No sense in taking the chance of causing embrittlement.
This can be simply controlled by not spraying with water while the steel is bright red in color.
Deliberate heating and cooling of pipe is often done to make corrections in alignment, or heat shrinking as in structural applications.
Cooling one side of a pipe of a pipe at one end will cause the other end to move toward the cooled side considerably.
This is usually done with a spray bottle or even a soaking wet rag.
NOT! recommended for high carbon materials like 4140 or for Chrome Moly.
Tim
Heating and cooling cycles have been used to induce thermal stresses that cause the member to move one way or another ans has been used for years to camber beams and girders as well as to flame straighten bent or distorted members. It works without causing metallurgical damage if the carbon steel or high strength low alloy steel members are not heated above the lower temperature of transformation. If the member is quenched and tempered, the temperature must be kept below the tempering temperature used by the manufacturer.
Most steels will experience plastic deformation when the temperature differential is more than about 220 degrees F. In short, the steel can be heated to temperatures well below the tempering temperature or the lower temperature of transformation (LTT) and still be used for the purpose of cambering or straightening members. If the temperature is held below the LTT and cooled with water or other cooling medium, there is no danger of hardening.
Best regards - Al
That was kind of what I was getting at. I have never had a situation where I used anything to cool a weld faster. It goes against the grain with me. If anything, I would slow the cooling process as much as possible, to allow proper relief to the weld and base material.
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