Effect of Pre- and Post Heating on Weld Cracking of Low Alloy Steels (Report 2)
Pre-and Post-Heating Conditions in Relation to Chemical Composition and Sturcture
1984 Volume 2 Issue 1 Pages 39-46
Details
1984 Volume 2 Issue 1 Pages 39-46
The Application of supplementary heat to a weld joint befor or after welding have been studied using a mild steel, medium carbon steels, 50 to 100 kg/mm2 high tensile steels, low alloy steels, martensitic stainless steels and cast steels.
The results indicate that (1) When preheating is applied for preventing cold cracking in heat-affected zone, a new carbon equivalent, i.e. Pre. Ceq.=C+0.06Mn+0.03Ni+0.06Cr+0.10Mo, is useful in predicting the cracking susceptibility of a wide variety of steels above-mentioned, (2) the critical preheat and interpass temperatures are reduced by using postheating, (3) these temperatures must be held till postheating at the temperatures above the critical point (T2c) at which hydrogen-induced cracking can not occur, (4) the T2c depends on the chemistry of steel, and the T2c values may be given by T2c(°C)=455 Post Ceq. -110, Post Ceq.=C-0.08Si+0.20Mn+0.03Ni+0.05Cr+0.12Mo+0.84V, and (5) it is desirable for avoiding hot cracking that the preheat and interpass temperatures are lower than Ms point.
