摘要:
A method is provided with which a bearing steel, even when obtained from an ingot, is made to have a segregation part reduced in the degree of segregation and maximum inclusion diameter. The ingot contains 0.56-0.70 mass% C, 0.15-0.50 mass%, excluding 0.50 mass%, Si, 0.60-1.50 mass% Mn, 0.50-1.10 mass% Cr, 0.05-0.5 mass% Mo, up to 0.025 mass% P, up to 0.025 mass% S, 0.005-0.500 mass% Al, up to 0.0015 mass% O, and 0.0030-0.015 mass% N, with the remainder comprising Fe and incidental impurities. The ingot has a degree of segregation of 2.8 or less and a predicted value of the maximum diameter of inclusions present in 30,000 mm 2 of the ingot, as calculated by extreme value statistics, of 60 µm or less.
摘要:
A method is provided with which a bearing steel, even when obtained from an ingot, is made to have a segregation part reduced in the degree of segregation and maximum inclusion diameter. The ingot contains 0.56-0.70 mass% C, 0.15-0.50 mass%, excluding 0.50 mass%, Si, 0.60-1.50 mass% Mn, 0.50-1.10 mass% Cr, 0.05-0.5 mass% Mo, up to 0.025 mass% P, up to 0.025 mass% S, 0.005-0.500 mass% Al, up to 0.0015 mass% O, and 0.0030-0.015 mass% N, with the remainder comprising Fe and incidental impurities. The ingot has a degree of segregation of 2.8 or less and a predicted value of the maximum diameter of inclusions present in 30,000 mm 2 of the ingot, as calculated by extreme value statistics, of 60 µm or less.
摘要:
Provide is a method for manufacturing a tapered plate having a tensile strength of 570 MPa or more capable of being subjected to high-heat input welding with a heat input of more than 300 kJ/cm. Specifically, the method includes heating to a temperature of 1000°C or higher and 1200°C or lower, a steel slab having a chemical composition containing, by mass%, C: 0.03% or more and 0.12% or less, Si: 0.03% or more and 0.5% or less, Mn: 0.8% or more and 2.2% or less, P: 0.015% or less, S: 0.0005% or more and 0.0050% or less, Al: 0.005% or more and 0.1% or less, Nb: 0.003% or more and 0.014% or less, Ti: 0.003% or more and 0.02% or less, B: 0.0003% or more and 0.0025% or less, N: 0.0030% or more and 0.0070% or less, Ca: 0.0005% or more and 0.0050% or less and the balance being Fe and inevitable impurities, in which expression (1) is satisfied, performing hot rolling on the heated slab in which plate thickness changes in the longitudinal direction so as to form a tapered shape at a finishing rolling temperature of 900°C or lower and equal to or higher than the Ar 3 point and then performing accelerated cooling on the hot-rolled steel plate down to a temperature of 500°C or lower: where N and Ti respectively represent the contents (mass%) of N and Ti.
摘要:
Provided is an austenitic stainless clad steel plate having excellent j oinability between a cladding metal and a base metal in addition to excellent corrosion resistance, especially sensitization resistance characteristics, and a method for producing the austenitic stainless clad steel plate. An austenitic stainless clad steel plate has a cladding metal and a base metal formed by being stacked to the cladding metal. The cladding metal includes a composition that contains, by mass%, C: 0.020% or less, Si: 1.00% or less, Mn: 2.00% or less, P: 0.045% or less, S: 0.030% or less, Ni: 12.00 to 15:00%, Cr: 16.00 to 18.00%, and Mo: 2.00 to 3.00%, and the balance is Fe and incidental impurities. The cladding metal includes an austenite grain structure of a partially recrystallized structure or a recrystallized structure. The austenitic stainless clad steel plate has a shear strength of 300 MPa or more.
摘要:
Provided is a high-strength thick steel plate for structural use having a thickness of 50 mm or more and excellent brittle crack arrestability which can be preferably used for ships and a method for manufacturing the steel plate. The steel plate with excellent brittle crack arrestability has a metallographic structure mainly including a bainite phase, a texture in which the integration degree I of the RD//(110) plane in a central portion in the thickness direction is 1.5 or more, and a Charpy fracture appearance transition temperature vTrs in a surface portion and the central portion in the thickness direction of -40°C or lower. Further, the steel plate preferably has the Charpy fracture appearance transition temperature and the integration degree I of the RD//(110) plane in the central portion in the thickness direction satisfying the relational expression (1) below: vTrs 1 / 2 t - 12 × I RD / / 110 1 / 2 t ≤ - 70 where vTrs (1/2t) : fracture appearance transition temperature (°C) in the central portion in the thickness direction and I RD//(110) [1/2t] : integration degree of the RD//(110) plane in the central portion in the thickness direction.
摘要:
The present invention provides a steel for nitrocarburizing having excellent mechanical workability before nitrocarburizing, and showing excellent fatigue properties after nitrocarburizing, which is suitable for applying in mechanical structural components for automobiles etc. prepared by adjusting the composition so that it contains in mass%, C: 0.01 % or more and less than 0.10 %, Si: 1.0 % or less, Mn: 0.5 % to 3.0 %, P: 0.02 % or less, S: 0.06 % or less, Cr: 0.3 % to 3.0 %, Mo: 0.005 % to 0.4 %, V: 0.02 % to 0.5 %, Nb: 0.003 % to 0.15 %, Al: 0.005 % to 0.2 %, and Sb: 0.0005 % to 0.02 %, and the balance including Fe and incidental impurities, and setting the area ratio of bainite phase to the whole microstructure to more than 50 %.