Metallurgical Study on the Reheat Cracking at the Weld Zone of Steel (Report 1)

Discussion on the Method for Evaluating the Sensitivity of Steel to Reheat Cracking

Abstract

The authors undertook a study on the reheat cracking testing method of steel by way of the stress relieving test, and the method for evaluating the sensitivity of steel to the reheat cracking.
The results of the study obtained are summaraized as follows:
1) The reheat cracking testing method by use of the weld thermal-restraint stress and strain-cycle simulator has the advantages of permitting the reheat cracking test to be made continuously in the heating and the holding processes.
Therefore, this method can be seen the stress at the time of occurrence of cracks in steel, the cracking temperature and the proceeding of the stress relieving until lead to cracks.
2) Judging from the results of reheat cracking test by use of the weld-reinforced test pieces, it has been evident that the cracking position, propagation proceses of cracks, geometry of the cracked fracture surface, the temperature at which the steel test piece was cracked, etc. which are the characteristic phenomena of the reheat crackings coincide with the phenomena obtained in others studies in the past.
For that reason, the present studying method of us is justifiable
3) It has been clear, furthermore, that the sensitivity of the test piece to the reheat cracking may be evaluated according to the quantity of plastic deformation, Δlp', as measured at the time of oc-currence of cracking.