Effects of Alloying Elements on the Extremely low Carbon Cast Steel (Report 3)

Effects of Alloying Elements on the 0.05-0.08%C Cast Steel

Abstract

As a 0.05-0.08% C cast steel is inferior in toughness but superior in strength to a 0.01 % C cast steel which was reported in the previous report, the effects of alloying elements on the toughness and mechanical properties of the 0.05-0.08% C caset steel were investigated.
Then the toughnesses of cast steels were summarized and compared with those of remelted casts of mild and high strength steel plates and electrode wires and also with those of their weld metals by CO₂-O₂ arc welding.
Consequently the results obtained were discussed in comparison with the results of weld metals by other researchers.
They are summarized as follows.
1) The toughness of the 0.05-0.08% C cast steel was improved by suitable additions of aluminium and nickel. The addition of chromium had a detrimental effect on the toughness of the 0.05-0.08% C cast steel, but it seemsto be effective to improve the toughness of the cast steel, if the carbon content of the cast steel is under 0.05%. The addition of molybdenum was not effective to improve the toughness of the 0.05-0.08% C cast steel.
2) Especially the transition temperature of the 0.08% C cast steel containing 0.002% Al was -40°C and lower than that of the 0.01 % C Mn-Si cast steel.
3) The tensile strength of the 0.05-0.08% C cast steel was scarcely influenced by additions of these alloying elements. Its value was about 55 kg/cm².
4) The impact vlaues of the 0.44% Ni-added and 0.002% Al-added 0.08% C cast steel were much higher than those of remelted casts of mild and high strength steee plates and electrode wires and their weld metals.
5) These experimental results with cast steels are in good coincidence with those of weld metals.