158results about How to "High fatigue limit" patented technology

The invention belongs to the material processing field and relates to a method for preparing double-scanning and spray forming high-speed steel under purification. First, a yttria partially stabilized zirconia ceramic filter is adopted to filter high-speed molten steel that is molten and refined in vacuum atmosphere; before the spray forming of the molten steel, gas washing operation is conducted on a working chamber and an atomizer chamber and high purity nitrogen is filled in the working chamber and the atomizer chamber with gas pressure close to 1atm; the uniformly refined high-speed molten steel is slowly poured into a heated pouring box, through which the molten steel is filtered; and through a draft tube, the molten steel is atomized into melt drip that is deposited on a depositor to form deposition blank. When the temperature of the deposition blank is lower than 200 DEG C, the deposition blank is taken out. In each step of operation of spray deposition, the method reduces harmful ceramic particles and oxides to be mixed in as well as the content of unfavorable elements such as gas, thus not only solving the segregation problem of the high-speed steel, but also improving the purity of the high-speed steel.

The invention relates to a super-high-strength hot-rolled steel plate and steel belt with good fatigue and broaching performance and a manufacturing method of the steel plate and steel belt. The steelplate and steel belt are prepared from, by weight, 0.07-0.14% of C, 0.1-0.4% of Si, 1.55-2.00% of Mn, smaller than or equal to 0.015% of P, smaller than or equal to 0.004% of S, 0.01-0.05% of Al, smaller than or equal to 0.005% of N, 0.15-0.50% of Cr, 0.1-0.35% of V, 0.01-0.06% of Nb, 0.15-0.50% of Mo, smaller than or equal to 0.02% of Ti and the balance Fe and unavoidable impurities. Meanwhile,the condition 1.0<=[(Cr / 52) / (C / 4)+(Nb / 93+Ti / 48+V / 51+Mo / 96) / (C / 12)]<=1.6 needs to be met. For the super-high-strength hot-rolled steel plate and steel belt, the tensile strength is greater than or equal to 780 MPa, the yield strength is greater than or equal to 660 MPa, the tensile fatigue limit (circulation of 10,000,000 times) FL is greater than or equal to 570 MPa, or the ratio of the fatigue limit to the tensile strength FL / Rm is greater than or equal to 0.72, and the broaching rate meets the conditions that if an original hole is a punched hole, the broaching rate is greater than 85%; if the original hole is a reamed hole, the broaching rate is greater than 120%.

A backrest is provided, whereby a frame-shaped base structure of which is made of a dimensionally stable plastic, The base structure being formed from beams. The frame-shaped base structure includes at least one functional element between the beams, and the at least one functional element is made only of a plastic and / or as a plastic-coated insert. Injection molding is proposed as a production method.