5results about How to "Uniform grain structure" patented technology

The invention relates to the technical field of bolt production, and particularly discloses a high-strength bolt machining process and device. Comprising the following steps: S1, material selection: selecting an alloy steel blank containing C, Si, Mn, Cr, Mo, V and the balance of Fe; s2, cold heading forming is conducted, specifically, the alloy steel blank is placed in a multi-station cold heading machine, and a bolt blank is formed through continuous cold heading and forging; s3, heat treatment is conducted, specifically, the bolt blank is subjected to quenching treatment and then subjected to tempering treatment, and a bolt base body is obtained; and S4, surface treatment is conducted, specifically, phosphating treatment is conducted on the surface of the bolt base body in sequence to form a phosphating layer, the composite coating is coated, and the high-strength bolt is obtained. The high-strength bolt machining process can be used for manufacturing connecting components requiring high reliability under complex working conditions such as heavy load, vibration and impact, and the high-strength bolt machining process has the advantages that the toughness, fatigue resistance and delayed fracture resistance are improved while high strength is kept.

The application relates to the technical field of crystallizers, and discloses a manufacturing process of an ultra-large-specification crystallizer copper pipe, a semi-continuous casting machine set, an oil press machine set, an extruding machine set, a curve type box type heating furnace set and a high-precision Fanuc gantry five-axis machining center set, which are used for continuously casting the copper pipe group, extruding the copper pipe group, twice extruding the copper pipe group, heating and cooling the copper pipe group and machining the copper pipe group. The manufacturing process of the ultra-large-specification crystallizer copper pipe reduces the problems such as shrinkage and shrinkage hole of the copper pipe group, rapidly reversely extrudes the copper pipe group, ensures that the copper pipe group is free of cracks, the grain structure is uniform, the surface hardness is high, residual internal stress is eliminated during the copper pipe group machining process, the machining precision is improved, the electroplating precision and capacity of the copper pipe group through the ultra-large automatic electroplating tank are improved, the electroplating requirements of the copper pipe group are ensured, thus avoiding the influence of bubbles on the electroplating effect of the copper pipe group and improving the finished product quality of the copper pipe group.

The invention discloses a method for refining 316L stainless steel grains based on a selective laser melting technology, and belongs to the technical field of metal material additive manufacturing. According to the method, Fe-C-B alloy powder is added, a Fe-B or Fe-B-Cr type compound is formed to serve as a heterogeneous nucleation core when the 316L stainless steel component is manufactured through selective laser melting, columnar crystal epitaxial growth is inhibited, and grain refinement is achieved. By means of the synergistic effect formed by Fe, C and B, the negative influence of the SLM technology on the 316L stainless steel forming process is avoided, the advantages of the SLM technology are fully exerted in the 316L stainless steel component forming process, accordingly, the 316L stainless steel component high in compactness and excellent in comprehensive performance can be formed only through SLM, the method is stable in process, low in crack sensitivity and high in yield, and the production cost is reduced. The method has remarkable advantages in the field of additive manufacturing of high-performance 316L stainless steel components.

The invention belongs to the technical field of electrical materials, and discloses a process method for improving the pressure resistance of a copper-chromium contact prepared from a vacuum casting base material, which comprises the following steps: preparing a copper-chromium contact part and carrying out a pressure resistance test, recording a pressure resistance result, carrying out solid solution and aging treatment on the copper-chromium contact part, and obtaining the pressure resistance of the copper-chromium contact part. The copper-chromium contact part subjected to solid solution and aging treatment is subjected to accurate grinding treatment, the surface of the copper-chromium contact part subjected to ultrasonic treatment is covered with industrial alcohol, ultrasonic treatment is carried out, the copper-chromium contact part subjected to ultrasonic treatment is put into a temperature constant-temperature box to be dried, then a voltage withstanding test is carried out, and a voltage withstanding test result is recorded. Through solid solution aging, accurate grinding, ultrasonic treatment and drying treatment, the internal grain structure of the copper-chromium contact is homogenized, the surface roughness of the contact is obviously reduced, the surface quality of the contact is improved, the voltage withstanding level of a part is improved, the surface roughness is kept to be smaller than or equal to Ra2, and therefore the breakdown voltage of the part is improved.

This invention provides a variable-temperature forging process for difficult-to-deform lightweight aluminum / magnesium alloys. The process involves determining the recrystallization temperature to lock in the preheating temperature; heating the difficult-to-deform aluminum or magnesium alloy billet to the preheating temperature; maintaining a die temperature 50-200°C higher than the billet temperature; implementing an initial temperature transfer deformation process on a forging press, with the die at a high temperature and the billet at a low temperature; ensuring the die temperature is 50-200°C higher than the billet temperature; performing plastic deformation at the same temperature for both the die and the billet when the forging deformation reaches 1 / 3-2 / 3 of the stage; maintaining pressure with the die temperature 50-100°C lower than the billet temperature; water quenching the formed forging, followed by aging heat treatment. This variable-temperature forging process for difficult-to-deform lightweight aluminum / magnesium alloys reduces the tendency for deformation damage during deformation, ensures low-temperature deformation of the workpiece without damage or cracking, improves the deformation uniformity of the workpiece, and optimizes its microstructure and mechanical properties.