4results about How to "Reduce stress cracking" patented technology

This invention belongs to the field of aluminum alloy materials technology, and relates to a high-strength and ductile aluminum alloy and its preparation method. The alloy comprises, by mass fraction: 2-6% Mg, 0.4-0.9% Mn, 0.2-0.6% Si, 0.05-0.15% Sn, Fe≤0.15%, Ti≤0.1%, with the balance being Al. By introducing Sn, a low-melting-point MgSiSn primary phase is formed in the as-cast stage, and transforms from a continuous network to a discontinuous granular structure during homogenization heat treatment, weakening the adverse effects of brittle intermetallic compounds at grain boundaries. Simultaneously, Sn dissolved in the aluminum matrix forms a nanoscale MgSiSn precipitate during homogenization, serving as a heterogeneous nucleation core for the Mn-containing second phase, lowering its nucleation energy barrier, and promoting high-density, fine, and uniform precipitation, thereby achieving a synergistic improvement in the alloy's strength and ductility.

The application relates to the technical field of alloy steel, in particular to a 90 ksi steel grade alloy steel for extra-high voltage wellhead equipment and a preparation method thereof. The raw material components of the alloy steel include, by mass percentage, C: 0.25-0.35%, Si: 0.15-0.35%, Mn: 0.40-0.90%, P<=0.020%, S<=0.010%, Cr: 1.90-2.50%, Ni<=0.10%, Mo: 1.00-1.50%, V: 0.01-0.10%, Nb: 0.01-0.10%, Al: 0.01-0.10%, B: 30-60 ppm, and the rest is Fe and inevitable impurities. The 90 ksi steel grade alloy steel for extra-high voltage wellhead equipment provided by the application has high strength and good hydrogen sulfide corrosion resistance as a wellhead forging material.

The present application relates to a kind of quick heat-conducting sand mould material and its preparation method, and the sand mould material is mainly composed of heat-conducting aggregate and high-temperature working matrix, and the raw material is alpha-alumina powder, additional high-thermal-conductivity aggregate, magnesium oxide aggregate, binder RTV silicone rubber, wherein the main raw material of heat-conducting aggregate is sintered magnesium oxide particle aggregate, graphite particle, water glass solution and silica ash.By using the present application as a casting mold, the stress cracking phenomenon on the surface of zirconium-chromium corundum blank is significantly reduced, and the product qualification rate of the material is significantly increased.The present application can effectively solve the stress cracking problem during the annealing process of melting and casting zirconium-chromium corundum.

The invention belongs to the technical field of artificial joint preparation, and particularly relates to a preparation method of a titanium-carbon nano multilayer composite wear-resistant coating material on the surface of an artificial joint. The method comprises the steps that S01, titanium alloy for 3D printing is prepared to serve as a base material, and the base material is pretreated; s02, alternately preparing a Ti-TiN layer with an interface fusion characteristic by adopting cathode arc ion plating and anode layer ion beam; and S03, preparing the amorphous carbon lubricating layer. The titanium-carbon composite protective coating material with the multi-layer interface fusion characteristic is prepared on the basis of an alternating gradually-changing arc ion plating method by providing a composite structure thought that a bonding layer on the surface of a base body is strengthened, and a middle energy absorption layer and a top lubricating layer of an interface fusion structure are combined into a whole.