Abstract: A relatively low cost, high strength, high toughness bar and sheet steel, which is substantially non-susceptible to the formation of delayed surface cracks in the as-rolled condition and its method of preparation, are provided, the constitution of the steel on a percentage mass to mass basis being as follows:C=0.21-0.28Mn=0.80-1.80Cr=1.60-2.10Si=0.35 maximumAl=0.02-0.05P and S each=0.025 maximumFe=the balance;the steel being characterized in that its composition is such that, upon air cooling following rolling, the transformation temperature of the steel during the cooling is at a sufficiently high level to ensure that there is sufficient thermal contraction possible after the transformation has been completed to accommodate at least the thermal expansion which had taken place during the transformation.

Abstract: A steel for the production of as rolled products (products requiring no subsequent reheat treatment after finish rolling) for use in underground equipment and tools is provided which has a hardness in the order of 500 HV (Vickers); a Charpy toughness value at 20.degree.C. of 35 to 50 Joule; an excellent to fair corrosion resistance in simulated mild mine water as herein defined; and good to fair weldability; the steel having the following constitution on a percentage mass per mass basis:C=0.13 to 0.19; Cr=8.5 to 12.0;Ni=0 to 3.0; Si=0.10 to 0.5;Mn=0.3 to 0.9; Mo=0 to 1.4;Ti=0.01 to 0.04; Nb=0 to 0.06;Al=0.02 to 0.06; P=0.035(max); andS=0.02 (max); the balance being Fe.