The selection and design of special alloy steel mainly include material selection, material design, and product design.
1) Material selection principles:material performance, process adaptability, and economic principles;
2) Material design:Product design (product function, manufacturing process, product cost accounting) and material design.
Selection of Special Alloy Steel
The important basis for material selection is to find materials that can meet the determined service environment and also meet the requirements of both basic and auxiliary performance.
Design of Special Alloy Steel
In the design of special alloy steel, the fundamental task that needs to be completed is to meet the performance requirements of the service environment of engineering components or mechanical parts. The performance mainly includes:1) basic parameters (strength, plasticity, toughness, fatigue limit, etc.), which are directly used for design calculations; 2) The comprehensive parameters (wear resistance, corrosion resistance) can be used to determine the order of material selection. The performance of special alloy steel is influenced by its composition, internal microstructure, impurities and defects, surface structure, and stress state, among which chemical composition and structural characteristics have the main influence.
The design of special alloy steel first involves composition and microstructure design, with the foundation mainly including:
1) The composition of steel, alloying elements, interactions between elements, and the morphology, distribution, and characteristics of the constituent phases formed by the constituent elements;
2) The physical essence and basic theory of the strengthening and toughening mechanism, process performance, heat resistance, corrosion resistance, and wear resistance of steel;
3) The quantitative or semi quantitative relationship between the chemical composition, microstructure, strength, plasticity, and toughness of steel;
4) The evolution process and characteristics of the morphology and distribution of the constituent phases of steel under the coupling effect of thermal media;
5) The deformation and strengthening of the composition phase of steel, as well as the changes and fractures during service life.
The above five factors are interrelated and affect each other. The selection of organizational structure needs to ensure that the process is adaptable throughout the entire manufacturing process, and also consider the economy of each process to avoid the occurrence of high cost special alloy steel that does not meet the service environment.
Design of Special Alloy Steel Products
The special alloy steel product design system includes product concept, service performance, product design, product manufacturing, surface engineering, test evaluation, product use, and product maintenance systems. In product design, the product should be viewed as a system and designed using systems engineering methods. The product design process adopts a holistic design concept that combines top-down and bottom-up approaches, with the characteristics of continuous iteration, gradual convergence, and repeated evaluation.
Product cost
The product cost mainly includes the full life cycle expenses of the product, including all expenses related to product design, manufacturing, use, and environmental treatment. Quantifying the risk of design or design revisions is a necessary component of the design process.