2023 AUG 21 (NewsRx) -- By a
News Reporter-Staff News
Editor at Daily Asia Business -- Researchers detail new data in metallurgy. According to news reporting from the
JSW Steel Ltd.
by NewsRx journalists, research stated, “Resistance spot welding studies at varying current with an 8 mm electrode on steel grades DP980, DP690, TRIP980 and TRIP780, established that peak strength with sound weld could be achieved at a current range of 9 to 10 kA, where the nugget diameter was between 6.9 and 7.5 mm. The joint efficiency, measured as hardening ratio was highest in TRIP690 at 2.22 and for higher strength grade it was between 1.37 to 1.51.”
Our news journalists obtained a quote from the research from
JSW Steel Ltd.
: “The softening ratio in the HAZ associated with tempering of preexisting martensite, was 0.86 to 0.9. Higher fusion strength was associated with alloying content that increased resistance that increased weld pool fusion that enhanced the nugget diameter and hence the strength. The TRIP steel at high cooling rate showed martensite and retained austenite and the DP steel showed martensite content in higher grade and dispersed ferrite with martensite in the lower DP grade. The Tensile shear strength was lowest (16kN) for DP780, while for other grades it is between 20 to 22 kN. The strength enhancement in TRIP steel was due to higher weld diameter at higher current, where partial pull out failure mode was observed. At lower current, the interfacial pull out failure mode was observed with poor fusion and at high currents partial pull out at HAZ is observed. The Coach peel strength was highest at 3.2 kN for DP780, 2.2 kN for DP980, 2 kN for TRIP 690 and 1.7kN for TRIP 980 and follows the trend in TSS. The observed failure may be attributed to the high fusion strength in TRIP steel due to sound nugget and a microstructure of martensite with retained austenite.”
According to the news reporters, the research concluded: “The lower strength with DP steels is attributed to low alloyed lath martensite in DP 980 and the lower grade DP780 is softer associated with ferrite dispersion in martensite. At very high currents, the fusion is good but there is pull out at HAZ due to the softening associated with the tempering of preexisting martensite that influenced the failure at HAZ failure mode.”
For more information on this research see: Weldability study of dual phase and transformation induced plasticity automotive steels.
Journal of Mining and Metallurgy
. Section B: Metallurgy, 2023,59(1):155-167. (
Journal of Mining and Metallurgy
. Section B: Metallurgy - http://www.doiserbia.nb.rs/journal.aspx?issn=1450-5339). The publisher for
Journal of Mining and Metallurgy
. Section B: Metallurgy is Technical Faculty, Bor.
A free version of this journal article is available at https://doi.org/10.2298/JMMB220712014A.
Our news editors report that additional information may be obtained by contacting Akela A.K.,
JSW Steel Ltd.
Toranagallu, Bellary Karnataka, India. Additional authors for this research include Shashikumar H., Mohapatra J.N., Singh R., Kumar D.S., Balachandran G.
(Our reports deliver fact-based news of research and discoveries from around the world.)
