摘要:
A rolled round steel material for a steering rack bar contains C in an amount of 0.38 to 0.55%, Si in an amount of 1.0% or less, Mn in an amount of 0.20 to 2.0%, S in an amount of 0.005 to 0.10%, Cr in an amount of 0.01 to 2.0%, Al in an amount of 0.003 to 0.10%, B in an amount of 0.0005 to 0.0030%, Ti in an amount of 0.047% or less, Cu in an amount of 0 to 1.0%, Ni in an amount of 0 to 3.0%, Mo in an amount of 0 to 0.50%, Nb in an amount of 0 to 0.10%, V in an amount of 0 to 0.30%, Ca in an amount of 0 to 0.005%, and Pb in an amount of 0 to 0.30%, a remaining portion being constituted by Fe and an impurities, the impurities containing P in an amount of 0.030% or less and N in an amount of 0.008% or less, and has a chemical composition satisfying [3.4N≦Ti≦3.4N+0.02]. The microstructure is constituted by ferrite (F), lamellar pearlite (LP), and cementite (C), and in the latitudinal cross-section, in a region extending from a surface to a position located a distance of ½ the radius therefrom, the average particle diameter of F is 10 μm or less, the area percentage of LP is less than 20%, and the number of pieces of spheroidal cementite (SC) in C is 4×105 pieces/mm2 or more, and, in a central portion, the area percentage of LP is 20% or more and the number of pieces of SC is less than 4×105 pieces/mm2, and in the longitudinal cross-section, the average aspect ratio of F in a region extending from a surface to a position located a distance of ½ the radius therefrom is 3 or more. This steel material has a high base material toughness and good machinability without performing thermal refining.
摘要翻译:用于转向齿条的轧制圆钢材料含有C为0.38〜0.55%,Si为1.0%以下,Mn为0.20〜2.0%,S为0.005〜0.10% ,0.01〜2.0%的Cr,0.003〜0.10%的Al,0.0005〜0.0030%的B,0.047%以下的Ti,0〜1.0%的Cu, ,0〜3.0%的Ni,0〜0.50%的Mo,0〜0.10%的Nb,0〜0.30%的V,0〜0.005%的Ca, ,Pb为0〜0.30%,余量由Fe和杂质构成,杂质含量为0.030%以下,N为0.008%以下,含有化学物质 组成满足[3.4N≦̸ Ti≦̸ 3.4N + 0.02]。 微结构由铁素体(F),层状珠光体(LP)和渗碳体(C)构成,并且在横截面中,从表面延伸到位于半径的1/2的位置的区域中, F的平均粒径为10μm以下,LP的面积率小于20%,C中的球状渗碳体(SC)的片数为4×10 5个/ mm 2以上,在中央 部分,LP的面积百分比为20%以上,SC的片数少于4×105个/ mm 2,纵向剖面中,从表面延伸的区域的F的平均长宽比 位于其半径的1/2的距离处的位置为3以上。 该钢材具有高基材韧性和良好的机械加工性,而不进行热精炼。
摘要:
In order to provide a method for hardening a metal sheet material by means of which a particularly hard and scratch-resistant surface is produced on the metal sheet material, it is proposed that the method comprises the following: applying at least one peening stream to the metal sheet material, wherein at least one peening stream is applied to a front side of the metal sheet material and/or a rear side of the metal sheet material, respectively.
摘要:
Systems and methods to generate beneficial residual stresses in a material, clean, strip coatings from, or roughen surfaces by generating cavitation shock waves without damaging the surface of the material. Shock waves emanate through the target material from collapsing cavitation voids in and around a liquid jet to generate residual stresses without impinging the jet against the material, or by impinging the material at shallow angles, and without significantly damaging or deforming the surface of the target material.
摘要:
The present invention relates to a hot-rolled steel sheet applied as a material for home appliances, vehicles, or the like and, more specifically, to a hot-rolled steel sheet having excellent workability and anti-aging properties and a method for manufacturing the same. To this end, the present invention uses ultra-low carbon Al-killed steel so as to optimize the alloying elements thereof and the manufacturing conditions, thereby providing hot-rolled steel sheets having both excellent workability and anti-aging properties.
摘要:
A method for setting a shot-peening process condition includes a step of obtaining, for each of a plurality of peening conditions for a first combination as a combination of a shot peening processing apparatus and media, a saturation time based on a saturation curve indicating a change in an arc height value of an Almen strip against a projection time. The method includes a step of determining a first optimum peening condition corresponding to the first combination based on the saturation time.
摘要:
The present invention pertains to a method of applying surface mechanical attrition treatment (SMAT) with a plurality of balls for treating surfaces of metallic alloys under a set of specific conditions in order to obtain a metal substrate with high yield strength and hardness, low cytotoxicity, high cytocompability and hemocompatibility suitable for medical implant. The plurality of balls used in the present invention comprises 316L stainless steel balls or zirconium oxide (ZrO2) balls.
摘要:
A method of cavitation peening a workpiece is provided. The method includes discharging a flow of fluid towards the workpiece at a pressure and a flow rate that facilitates forming a plurality of cavitation bubbles, monitoring a feedback parameter associated with the plurality of cavitation bubbles, and determining a peening intensity of the plurality of cavitation bubbles based at least partially on a value of the feedback parameter.
摘要:
Provided is a method of treating a surface of a mold to achieve good demoldability and capable of preventing wearing of the mold by avoiding load concentration on one part of the surface of the mold. After a first blasting is performed on the surface of the mold to remove a hardened layer produced on the surface and/or to adjust the surface roughness, a second blasting is performed to create fine irregularities on the surface. Then, an elastic abrasive in which abrasive grains are carried on an elastic body, or a plate-like abrasive having a planar shape with a maximum length that is 1.5 to 100 times the thickness thereof, is ejected onto the surface of the mold at an inclined ejection angle such that the abrasive is caused to slide along the mold surface to flatten peaks of the irregularities created on the mold surface.
摘要:
Provided is a method of treating a surface of a mold to achieve good demoldability and capable of preventing wearing of the mold by avoiding load concentration on one part of the surface of the mold. After a first blasting is performed on the surface of the mold to remove a hardened layer produced on the surface and/or to adjust the surface roughness, a second blasting is performed to create fine irregularities on the surface. Then, an elastic abrasive in which abrasive grains are carried on an elastic body, or a plate-like abrasive having a planar shape with a maximum length that is 1.5 to 100 times the thickness thereof, is ejected onto the surface of the mold at an inclined ejection angle such that the abrasive is caused to slide along the mold surface to flatten peaks of the irregularities created on the mold surface.
摘要:
A method for producing a carbonitrided member comprising the steps of carburizing a steel part having a composition of, by mass percent, C: 0.10 to 0.35%, Si: 0.15 to 1.0%, Mn: 0.30 to 1.0%, Cr: 0.40 to 2.0%, S: 0.05% or less with the balance being Fe and impurities in a carburizing atmosphere of 900 to 950° C. The carburized steel part is carbonitrided in a carbonitriding atmosphere with the temperature of 800 to 900° C. and the nitrogen potential of 0.2 to 0.6%. The carbonitrided steel part is qhenched and then shot peened. The shot peening treatment may be further performed while heating to a temperature not higher than 350° C. or immediately after heating to a temperature not higher than 350° C. After quenching, the shot peening treatment may be further performed after tempering in the temperature range exceeding 250° C. and not higher than 350° C.