A Study of Weld Cracking of Austenitic Stainless Steel (Report 2)

Microfissuring Test

Abstract

A study has been made of the effects of weld heat input, ferrite percentage and type of electrode on the microfissuring in multibeads deposited with stainless steel electrodes, D347, D308, D308L and 16- 8-2 (Cr-Ni-Mo).
The results are summarized as follows:
1) It was confirmed that microfi ssures in the austenitic stainless steel welds occured in intercrystalline.
2) The presence of ferrite about 5% or more in deposited metal obviated the microfissuring in multibeads.
3) The microfissuring was very sensitive to type of electrode coating and the lime coated electrode was remarkably resistant of microfissuaing than the lime-titania coated.
4) The multibeads deposied with the electrode D347 showed more sensitivity to microfissuring than those deposited with electrodes D308, D308L and 16-8-2 (Cr-Ni-Mo).
5) The microfissures appeared with random direction and were located preferentially along and adjacent to the boundary of a bead. Thus the reheating of a bead by the following layer may be a possible cause of microfissuring.
6) The increase of heat input and the accompanying decrease of cooling rate was found to be effective to reduce microfissures. The increase of welding current was very useful to obviate microfissuring.