Full Description

This program to investigate the validity of conventional carbon equivalent formulas applicable to the weldability of nine low-carbon micro-alloyed steels for marine structures included in its scope the determination of CGHAZ hardness as a function of cooling time from 800 to 500C, measurement of cooling times/cooling rate as a function of welding conditions, validation of calculation methods, the categorization of HAZ microstructures and hydrogen assisted cracking by three different methods namely: the Battelle Underbead Cracking, UT-Modified Hydrogen Sensitivity and Implant Cracking tests. The steels tested were: HSLA-80-1, HSLA-80-2, HSLA-80M, HSLA-100, HSLA-130, HY-130, DQ-125, DQ-8O, and AC-50.

Six steels, HSLA-80-1, HSLA-80-2, HSLA-80M, HSLA-100, HSLA-130, and DQ-8O, contain copper (>1 wt.%) and were strengthened by the precipitation of epsilon-copper. Modern thermomechanical controlled processing (TMCP) was employed in the production of DQ-8O, DQ-125 and AC-50, whereas the Navy HSLA steels were of quenched and aged variety. The literature review conducted at the inception of this program revealed the effects of TMCP and cleanliness of the "new" steels in reducing the hardenability of steels by providing more sites for ferrite nucleation. Therefore, the carbon equivalent formulas applicable to the conventional steels generally overestimate the hardenability of the TMCP steels.

Product Details

Published: 1990 Number of Pages: 109 File Size: 1 file , 4.3 MB