Abstract:
Invention relates to a method of producing a crown wheel with near-net shaped as-forged teeth having continuous grain flow lines and having minimal machining allowance. The method of invention comprises the steps of making ring using hammer forging and ring rolling technique followed by blocker and finisher forging step for manufacturing of gear teeth on the ring and after which a cold coining operation is performed on the finished forging to achieve near net shape of gear teeth. The cold-coining operation allows a reduced machining allowance of up to 0.3mm but with minimal dimensional variation of teeth. These near net shaped teeth's are further finished to final shape by grinding operation. The forging of near net shape gear teeth profile is carried out using any type of press capable of applying required force. Representative Figure: Figure 3
Abstract:
Provided is a case hardening steel which has excellent fatigue characteristics and is obtained at a relatively low production cost. This case hardening steel is configured to have a component composition which contains 0.10-0.30% of C, 0.10-1.20% of Si, 0.30-1.50% of Mn, 0.010-0.030% of S, 0.10-1.00% of Cr, 0.0005-0.0050% of B, 0.005-0.020% of Sb and 0.0150% or less of N, and which additionally contains Al in an amount satisfying 0.010% ≤ Al ≤ 0.120% in cases where B - (10.8/14)N ≥ 0.0003%, and in an amount satisfying 27/14[(N - (14/10.8)B + 0.030] ≤ Al ≤ 0.120% in cases where B - (10.8/14)N
Abstract:
Metal components subject to wear or contact fatigue in a first area, and subject to bending, axial and/or torsional stress loading in a second area comprise a surface hardened, first surface layer in the first area; and a surface compressive-stress treated, second surface layer in the second area. The second surface layer has a material hardness different from, and typically lower than the first surface layer, and induced residual compressive stress to improve fatigue strength. Example components described include a gear, a cog, a pinion, a rack, a splined shaft, a splined coupling, a torqueing tool and a nut driving tool. A hybrid manufacturing process is described, including area-selective surface hardening combined with a process to add compressive stress to fatigue failure prone areas.
Abstract:
This heat treatment of bearing steel comprises annealing and hardening. Hardening is carried out after annealing and after the manufacture of structural parts from this steel. The first part of the annealing process is heating of the steel at a rate of more than 1 °C/s to a temperature in the range between 750 °C and 900 °C. It is followed by holding at the temperature achieved for at least 400 seconds. This is followed by cooling at a rate higher than 0.02 °C/s to a temperature, at which austenite begins to transform to ferrite and carbides. In the next step, there is cooling to such temperature and at such rate that complete transformation of austenite to ferrite and carbides takes place at least in the desired location of the steel. The cycle of heating, holding and cooling is carried out at least once. Then the steel is cooled to the ambient temperature. In the preferred embodiment, the quenching temperature during subsequent hardening is lower than the quenching temperature of the conventionally annealed steel in question. The steel may be heated by induction.
Abstract:
A method for forming a component utilizing ultra-high strength steel and components formed by the method. The method includes the step of providing a flat blank of ultra-high strength 22MnB5 steel. The next step of the method is, cold forming the flat blank into an unfinished shape of a component while the blank is in an unhardened state. The method continues by providing an inert atmosphere. Then, heating the unfinished shape of the component in the inert atmosphere. The method proceeds by forming a finished shape of the component using a quenching die resulting in a fine-grained martensitic component material structure and enabling net shape processing to establish final geometric dimensions of the components.
Abstract:
Acier inoxydable martensitique, caractérisé en ce que sa composition est : - traces ≤ C ≤ 0,030%; - traces ≤ Si ≤ 0,25%; - traces ≤ Mn ≤ 0,25%; - traces ≤ S ≤ 0,020%; - traces ≤ P ≤ 0,040%; - 8% ≤ Ni ≤ 14%; - 8% ≤ Cr ≤ 14%; - 1,5% ≤ Mo + W/2 ≤ 3,0%; - 1,0% ≤ Al ≤ 2,0%; - 0,5% ≤ Ti ≤ 2,0%; - 2% ≤ Co ≤ 9%; - traces ≤ N ≤ 0,030%; - traces ≤ O ≤ 0,020%; le reste étant du fer et des impuretés résultant de l'élaboration; et en ce que sa température de début de transformation martensitique Ms calculée par la formule (1) Ms (°C) = 1302 - 28Si - 50Mn - 63Ni - 42Cr - 30Mo + 20AI - 12Co - 25Cu + 10[Ti - 4(C+N)] dans laquelle les teneurs des différents éléments sont exprimées en pourcentages pondéraux, est supérieure ou égale à 50°C, de préférence supérieure ou égale à 75°C. Pièce réalisée en cet acier, et son procédé de fabrication.