Effect of Ta Addition on Microstructure and Hardness of Low Alloy Cr-W Steels
Gökhan Arıcı Mesut Uyaner Mustafa ACARER
AbstractIn this study, low alloy Cr-W steels containing 3% and 5% Cr and 3% W as main alloying element were produced via casting in ceramic mold and then hot rolled. Steels were produced both without Ta and with 0.1% by weight Ta. The purpose of this study is to investigate the effects of addition of Ta as alloying element to the microstructure and hardness of low alloy Cr-W steels. Before microstructure characterization and hardness test all samples were heat treated. Heat treatments were performed as (annealing, air quenching) and (annealing, air quenching and tempering). Annealing were performed at 1100 ℃ for 1 hour and tempering were performed at 710 ℃ for 2 hours. Microstructures were analyzed by optical microscope and the Brinell hardness test was used to determine the hardness of steels. 3 Cr steel has a microstructure of ferrite and bainite. 3 Cr steels containing 0.1% Ta has a microstructure of ferrite and bainite, too. But Ta-containing 3 Cr steel has less ferrite than Tafree 3 Cr steel. 5 Cr steel has a microstructure of bainite and martensite. 5 Cr steels containing 0.1% Ta has a microstructure of bainite and martensite, too. But Ta-containing 5 Cr steel has less bainite than Ta-free 5 Cr steel. 5 Cr steels which annealed and air quenched have highest hardness and 5 Cr steel which annealed, air quenched and tempered has lowest hardness.