(1) The criteria for alloy design. There are 3 aspects.
①Strategic criteria. From the resource and energy considerations, the alloy is required to be abundant, in line with national conditions, energy saving, conducive to the promotion of applications and long-term considerations.
②Economic criteria. The requirement is economical. Low cost, high total economic benefits.
③Technical criteria. Requirement of performance, organization, structure optimization, can get the best organization state, to meet the performance requirements of wear-resistant materials.
(2) Carbon and alloying element analysis, low and medium Taikin wear-resistant steel alloy
Composition design mainly considers the role and content of C, Mn, Si, Cr, Mo and other micro halo elements.
①Carbon, is the key element that affects the organizational properties of low and medium Taikin wear-resistant steel, and its variation is large. There are low carbon (0.1% ~ 0.3%), medium carbon (0.35% ~ 0.45%), medium-high carbon (0.5% ~ 0.7%) and high carbon (0.8% ~ 1.2%). Different amounts of carbon can obtain different matching relationship between hardness and toughness, low carbon alloy toughness is high and hardness is low, high carbon alloy hardness is high and toughness is not enough, medium carbon alloy has high hardness and good toughness. At present, the amount of carbon in low alloy wear-resistant steel is mainly medium carbon (medium-high carbon), individual also use high carbon, such as Gcrl5. medium alloy wear-resistant steel is mostly used high carbon, in order to form excess carbide with the chromium in the steel to give full play to the role of chromium.
②Manganese, silicon, manganese is significantly improve the hardenability of the element, and China’s manganese resources are abundant, low price, and therefore become the main element of low-alloy wear-resistant steel, generally add 1% a 2%. Research found that when the amount of manganese in the range of 2% a 3%, with boron, can project bainite transformation zone, in a larger range of cold speed to get a horse organization, get air-cooled bainite steel. When the amount of silicon added to 2% to 3%, can strongly inhibit the bainite transformation in the precipitation of carbide, to obtain no carbide bainite, based on this, the domestic development of Ran new A-B low-alloy steel.
③Chromium, aluminum, chromium, aluminum are to improve the hardenability and stability of the same fire elements, molybdenum can also improve the toughness. Chromium is the main element of the alloy wear-resistant steel, its content can reach 4% ~ 7%, in the low alloy wear-resistant steel is generally added to 1% ~ 3%, molybdenum in the performance requirements of the higher will be added to the system, the content of 0.2% ~ 0.5%.
④Trace elements, Ti, Nh, V trace can refine the grain, improve toughness; trace boron can improve hardenability, but also in conjunction with Mn to obtain narrow cold bainite steel; rare earth elements (RE) can deoxidation, sulfur, remove harmful impurities, refine the grain, reduce dendritic segregation, improve toughness. Improve the quality of steel.
