Abstract: The present invention provides, at low cost, a valve spring steel having a tensile strength as high as 210 to 240 kgf/mm.sup.2 after oil tempering. The high strength spring steel comprises, based on weight, 0.65 to 0.85% of C, 1.90 to 2.40% of Si, 0.50 to 1.00% of Mn, 0.70 to 1.30% of Cr, 0.10 to 0.30% of Mo, 0.20 to 0.50% of V, 0.01 to 0.04% of Nb and the balance Fe and unavoidable impurities and is subjected to heating at temperature of 1,050 to 1,250.degree. C. and then to rolling so that carbides in the steel have a size of up to 0.15 .mu.m in terms of equivalent circle. A valve spring having a tensile strength as high as 210 to 240 kgf/mm.sup.2 after oil tempering and stabilized quality can be produced while the material cost is greatly reduced by decreasing costly alloying components as much as possible.

Abstract: Disclosed is a spring steel for a high corrosion resistant and high strength, which exhibits an excellent drawability without softening heat treatment after hot rolling, and which has a strength of 1900 MPa or more by quenching and tempering and an excellent corrosion resistance. The spring steel contains elements of C, Si, Mn and Cr, and elements of Ni and/or Mo in suitable amounts, the balance being essentially Fe and inevitable impurities, wherein the elements satisfy the following requirement:2.5.ltoreq.(FP).ltoreq.4.52.0.ltoreq.(FP/log D).ltoreq.4.0where D is a diameter (mm) of the rolled material,and FP=(0.23?C!+0.1).times.(0.7?Si!+1).times.(3.5?Mn!+1) .times.(2.2?Cr!+1).times.(0.4?Ni!+1).times.(3?Mo!+1) in which ?element! represents mass % of the element.

Abstract: The present invention provides a spring steel with excellent performance, characterized in that the spring steel is produced by making a spring steel contain an appropriate amount of at least one or more of Ti, Nb, Zr, Ta, and Hf, thereby generating fine inclusions including carbide, nitride, sulfides and/or their complex compounds, to make the inclusions exert the effect of trapping diffusive hydrogen whereby the resistance to hydrogen embrittlement is enhanced, wherein the size and number of the coarse inclusions are regulated, thereby suppressing the decrease of the fatigue life. The spring steel can provide a valve spring or a suspension spring or the like, with enhanced strength and higher stress resistance, together with improved resistance to hydrogen embrittlement and fatigue.

Abstract: A method for forming a spring which can reduce variations in the surface hardness and the thickness of the hardened layer when the spring is nitrided. Before nitriding the spring, the thickness of an oxide film formed on the surface of the spring is reduced to 1.5 .mu.m or less by electropolishing or any other suitable means so that the residual stress of the spring will be -5 kgf/mm.sup.2 to 5 kgf/mm.sup.2 near its surface. With this arrangement, it is possible to increase the surface hardness and the thickness of the nitrided layer of the spring obtained by nitriding.

Abstract: A process for producing a coil spring comprises steps of: cold drawing a wire comprising: C in an amount of 0.55 to 0.75% by weight; Si in an amount of 1.00 to 2.50% by weight; at least two primary metals selected from the primary metal group consisting of: Mn in an amount of 0.30 to 1.5% by weight; Ni in an amount of 1.00 to 4.00% by weight; Cr in an amount of 0.50 to 2.50% by weight; Mo in an amount of 0.10 to 1.00% by weight; at least one secondary metal selected from the secondary metal group consisting of: V in an amount of 0.05 to 0.60% by weight; Nb in an amount of 0.05 to 0.60% by weight; and the balance of substantially Fe; oil quenching and tempering the wire; hot tempering the wire, thereby preparing the tempered wire whose tensile strength .sigma.b falls in the range of from 1370 to 1670 N/mm.sup.2 ; cold coiling; hardening and tempering; grinding; gas nitriding; high strength two-stage shot peening; and low temperature annealing the tempered wire.

Abstract: A spring steel of medium strength and sufficient corrosion resistance prepared by simple procedures, and therefore, at a low cost, is provided. The spring steel has the alloy composition of: C 0.3-0.6%, Si 1.0-2.0%, Mn 0.1% to less than 0.5%, Cr 0.4-1.0%, V 0.1-0.3%, Ni more than 0.5% to 1.2%, Cu 0.1-0.3% and the balance of Fe, wherein S being at highest 0.005%, and [O], at highest 0.0015%. Addition of Ca 0.001-0.005% is preferable. In order to ensure clearly improved fatigue limit under corrosive environment to the conventional steel, SUP7, specific contents of S, Ni, Cr, Cu and V are chosen in the range set forth above. For the purpose of obtaining such a low hardness after normalizing at which annealing prior to processing is unnecessary contents of C, Si, Mn, Cr and Ni are further chosen in the above ranges.

Abstract: A low decarburization high toughness spring steel for an automobile suspending spring, and a manufacturing process therefor, are disclosed. In this steel, the effect of the sag resistance promoting element (Si) is maximized without reducing the carbon content, so that the problems of the decarburization and the lowering of the toughness (caused by the addition of silicon) should be solved during the manufacturing of the spring steel. The spring steel of the present invention is composed of in weight %: 0.5-0.7% of C, 1.0-3.5% of Si, 0.3-1.5% of Mn, 0.3-1.0% of Cr, 0.05-0.5% of V and/or Nb, less than 0.02% of P, less than 0.02% of S, 0.5-5.0% of Ni, and other indispensable impurities, the balance being Fe.

Abstract: A method of optimizing the distribution of inherent stress in springs intended for vehicle suspensions, especially in the rod cross-section of high-strength helical compression springs, whereby the springs are set and bombarded with balls. The springs are forwarded for the operations setting and bombardment at a gradient of strength prescribed for the particular rod cross-section.

Abstract: Disclosed is a spring steel for a high corrosion resistant and high strength, which exhibits an excellent drawability without softening heat treatment after hot rolling, and which has a strength of 1900 MPa or more by quenching and tempering and an excellent corrosion resistance. The spring steel contains elements of C, Si, Mn and Cr, and elements of Ni and/or Mo in suitable amounts, the balance being essentially Fe and inevitable impurities, wherein the elements satisfy the following requirement:2.5.ltoreq.(FP).ltoreq.4.52.0.ltoreq.(FP/log D).ltoreq.4.0where D is a diameter (mm) of the rolled material, and FP=(0.23[C]+0.1).times.(0.7[Si]+1).times.(3.5[Mn]+1).times.(2.2[Cr]+1).tim es.(0.4[Ni]+1).times.(3[Mo]+1) in which [element] represents mass % of the element.

Abstract: A low decarburization spring steel consisting essentially of, in weight percentages, 0.40 to 0.75% C, 0.15 to 2.50% Si, 0.30 to 1.20% Mn, 0.005 to 0.100% Al and 0.005 to 0.100% Se, and optionally at least one selected from the group consisting of 0.50 to 2.50% Ni, 0.20 to 1.50% Cr, 0.05 to 1.50% Mo and/or at least one selected from the group consisting of 0.01 to 0.50% V and 0.01 to 0.50% Nb, the balance being Fe and inevitable impurities. The spring steels of this invention considerably reduce decarburization during hot working or heat treatment without recourse to anti-decarburizing agents or special heat treatment equipment.

Abstract: A metastable austenitic, cold deformed "work hardened stainless steel for springs", with 17.0 to 19.0% Cr, 8.0 to 10.0% Ni, up to 0.03% C, 0.006 to 0.16% N, up to 1.0% Si, 1.0 to 2.0% Mn, up to 0.8% Mo, up to 0.045% P, up to 0.030% S, iron (Fe) and residuals, the alloy being used for spring manufacture, exhibiting good resistance to corrosion after cold deformation, exhibiting high mechanical properties and better resistance to corrosion than UNS S30200 steel, even when exposed to a tempered heat treatment. The steel is appropriate for use as wire rod, bars, wires, sheets and strip forms.

Abstract: A high-strength spring steel has a high fatigue limit and is characterized by restricting the number of oxide particle inclusion having a diameter of not less than 10 .mu.m in steel to not more than 12 particles/100 mm.sup.2.

Abstract: A hot rolled steel bar is subjected to controlled hot roll finishing and cooling conditions which, together with the composition of the steel and controlled subsequent heat treating and quenching conditions, enable the formation of a steel spring having both relatively high hardness and high toughness.

Abstract: A steel composition is provided having improved sag resistance and fatigue behavior properties adapting it to be suitable for coil and torsion bar suspension springs for passenger vehicles and light trucks of lesser weight. Critical to the composition is the use of vanadium in an amount of from about 0.05 to about 0.50 wt% or niobium in an amount of about 0.05 to about 0.20 wt%, sufficient nitrogen to ensure that the vanadium or niobium is in the form of vanadium nitride or niobium nitride respectively and the substantial absence of aluminum. The vanadium nitride or niobium nitride ensures fine grain formation and the improved properties. Other components may be present including carbon, silicon and chromium.

Abstract: Disclosed herein is a new method for continuous heat treatment to be applied to the production of oil tempered steel wires for springs having high strength and high toughness to meet the requirement for weight reduction.The heat treatments are applicable to a medium carbon low alloy spring steel which does not undergo martensitic transformation substantially upon oil hardening alone. It comprises performing two-step accelerated hardening consistin of oil hardening and immediately following water hardening and subsequently performing tempering. The medium carbon low alloy steel is one which consists 0.40-0.65% carbon and Si and Mn as essential components and further at least one species of Cr, Ni, Mo, and V, and have the chemical composition corresponding to and Mf point lower than 80.degree. C. (preferably 10.degree.-70.degree. C.). It is desirable that the oil be wiped from the steel wire after the oil hardening and before the water hardening.

Abstract: Disclosed is a high-strength spring steel containing C, Si, Mn, Ni, Cr, Mo, V and the like within the specified range, wherein the above components satisfy the following equation:550-333[C]-34[Mn]-20[Cr]-17[Ni]-11[Mo].gtoreq. 300where [C, Mn, Cr, Ni, or Mo] represents wt % of each component, and the average diameter of the non-metallic inclusions of oxides is specified. By use of the above steel, there can be obtained a high-strength spring steel having a tensile strength of 200 kgf/mm.sup.2 or more and being excellent in the fatigue characteristic and the sag resistance. Further, in the above steel, each content of C, Si, Ni, and Cr may be added to satisfies the following equation:50[Si]+25[Ni]+40[Cr]-100[C].gtoreq. 230where [Si, Ni, Cr or C] represents wt % of each component. Thus the corrosion fatigue characteristic is also improved.

Abstract: A spring steel containing 0.35 to 0.50% of carbon is refined to the hardness of .phi. 2.50 to 2.70 mm in Brinell indentation diameter (HBD) by rapid cooling for quenching and tempering. This spring steel is subjected to warm shot peening at a temperature of 150 to 300.degree. C. (423 to 573K) by using long-lived practical shots with the normal hardness of .phi. 2.65 to 2.80 mm in HBD, whereupon a high-strength spring is obtained having a compressive residual stress in its surface and enjoying the maximum shearing stress of 110 to 135 kgf/mm.sup.2 (1080 to 1325 MPa).

Abstract: The present invention relates to hollow elements prepared from alloys having shape memory characteristics and techniques for heating the elements to effect the martensite (or R-phase) to austenite transformation. In its most preferred embodiment, the invention relates to the use of shape memory alloys to prepare hollow springs or tubular beams, bending and torsional, and the preferred methods of heating the elements include passing an insulated resistance heating wire through the core thereof and applying a current, or applying two layers of coating to the inside or outside of the tube, one of which is insulating and the other of which is electrically conductive. In the latter example, application of current to the conductive coating will heat the element. It is also envisioned that hot fluid may be passed through the element as the heating technique.

Abstract: A spring steel containing 0.35 to 0.50% of carbon is refined to the hardness of .phi. 2.50 to 2.70 mm in Brinell indentation diameter (HBD) by rapid cooling for quenching and tempering. This spring steel is subjected to warm shot peening at a temperature of 150.degree. to 300.degree. C. (423 to 573 K.) by using long-lived practical shots with the normal hardness of .phi. 2.65 to 2.80 mm in HBD, whereupon a high-strength spring is obtained having a compressive residual stress in its surface and enjoying the maximum shearing stress of 110 to 135 kgf/mm.sup.2 (1080 to 1325 MPa).

Abstract: A flat spring hose clamp having an improved resistance to brittle fracture and a method for manufacturing the same are disclosed, the hose clamp being made of a steel having a steel composition consisting essentially of, by weight %:C:0.30-0.70%,Si: 0.70% or less,Mn: 0.05-1.00%,P: 0.030% or less,S: 0.020% or less,Cr: 0.50-2.00%,Mo: 0.10-0.50%,Nb: 0.005-0.100%,sol. Al: 0.10% or less,N: more than 0.0020%, but not more than 0.015%,Ti: 0-0.10% and/or B: 0-0.0020%,and a balance of Fe and incidental impurities, and the steel possessing a uniform bainite structure.

Abstract: Disclosed is a high strength spring steel consisting of, in weight percentage, 0.50 to 0.70% C, 1.00 to 2.50% Si, 0.30 to 1.20% Mn, 0.80 to less than 1.20% Cr, 0.05 to 0.3% Mo, 0.05 to 0.30% V, 0.01 to 0.30% Nb, 0.005 to 0.100% Al and the balance being Fe and unavoidable impurities. The steel of the present invention has a high hardness coupled with high toughness and is very useful, especially for springs used in suspension devices or other various industrial machines.

Abstract: The present invention relates to a high-strength coil spring useful for an engine and other high-strength springs requiring a high fatigue-resistance and a method of producing the same.In general, a higher tensile strength is desired for spring materials but it has been known that if a tensile strength exceeds a certain limit, a toughness and a fatigue resistance are contrarily reduced.In addition, a coil spring has been used after forming and then being subjected to a quenching treatment followed by being subjected to a shot peening treatment to add a compressive residual stress to a surface thereof but an effective shot peening treatment gives a surface roughness Rmax of 6 to 20 .mu.m, so that not only it has been impossible to remove surface defects having a surface roughness of 6 to 20 .mu.m or less but also impressions due to the shot peening have covered the surface defects to be turned into injured portions and fatigue nuclei in many cases.

Abstract: Disclosed is a high strength spring steel consisting of, in weight percentage, 0.40 to 0.70% C, 0.50 to 2.00% Si, more than 0.50 to 1.50% Mn, 0.50 to 2.50% Ni, 0.20 to 1.50% Cr, more than 0.60 to 1.50% Mo, 0.01 to 0.50% V, 0.01 to 0.50% Nb, 0.005 to 0.100% Al and the balance being Fe and unavoidable impurities. The steel of the present invention has a high hardness coupled with high toughness and is very useful especially for springs used in suspension devices or other various industrial machines.

Abstract: A method of preparing a leaf spring having a heating step in which a raw material of a leaf spring is heated to austenite range temperature, a rolling step in which the above heated material is formed to a desirable shape, a working step in which the above rolling material is cut to a fixed length to form a chip hole, a bolt hole or the like, and a cooling step in which a camber is given to the above working material to cool to hardening in his state.Other five modified methods are also described.

Abstract: A spring steel having a good durability and a good sag-resistance consisting essentially of by weight 0.35-0.55% carbon, 1.80-3.00% silicon, 0.50-1.50% manganese, 0.50-3.00% nickel, 0.10-1.50% chromium, 0.01-0.05% aluminum and 0.010-0.025% nitrogen, the remainder being iron and inevitable impurities.The spring steel has been completed for the purpose of obtaining a spring steel having a high toughness in a high hardness of not less than HRC 55 and having a good sag-resistance, in particular examining the contents of nickel, chromium and nitrogen in addition to the carbon content.

Abstract: A high strength spring is made of steel of which composition consists of 0.6 to 0.7 wt % of C, 1.2 to 1.6 wt % of Si, 0.5 to 0.8 wt % of Mn, 0.5 to 0.8 wt % of Cr, 0.05 to 0.2 wt % in total of one or more than one of V, Mo, Nb and Ta and the balance of Fe and inevitable impurities. The steel is limited in particle size of non-metallic inclusions in such a way that the maximum particle size of the non-metallic inclusions is equal to or smaller than 15 .mu.m. The spring is applied at a portion adjacent the outer surface thereof with a residual compression stress in such a way that the maximum of the residual compression stress ranges from 85 to 110 Kgf/mm.sup.2. The spring is further process so as to have such a surface roughness that is equal to or smaller than 15 .mu.m.

Abstract: A composite metal spring material, and formed electrically conductive contact spring members made from the material, comprise metallurgically bonded layers of copper and stainless steel of selected compositions which are subjected to a novel sequence of heat-treating steps for providing the spring materials and members with spring characteristics of improved strength and stability.

Abstract: A high-strength steel for valve springs, consisting of 0.50-0.70 wt. % of carbon, 1.50-2.50 wt. % of silicon, 0.50-1.20 wt. % of manganese, 1.50-2.50 wt. % of nickel, 0.50-1.00 wt. % of chromium, 0.20.0.50 wt. % of molybdenum, 0.15-0.25 wt. % of vanadium, and the balance being iron and inevitably included inclusions. Also disclosed is a process for producing such a high-strength steel, which includes a step of minimizing oxygen in a melt of the steel, so as to reduce the oxygen content of the steel to 15 ppm or less, and a step of adding calcium to the melt and thereby controlling the form of the inclusions. The process may further include a step of minimizing titanium and nitrogen in the melt, so as to reduce the titanium and nitrogen content of the steel to 50 ppm or less, and 60 ppm or less, respectively.