Standard Update Notice: GB/T 42124.3-2025 came into effect on December 1, 2025, replacing GB/T 6414-2017. This page retains information from the old standard for reference in historical drawings and old projects; for new projects, please prioritize checking the current standard and contractual agreements. View the new standard GB/T 42124.3-2025, tolerance tables, and machining allowance instructions. Dimensional accuracy of castings is one of the important quality indicators of castings. Casting dimensional tolerance standards are the objective basis for measuring casting dimensional accuracy. Haijin Stainless Steel strictly adheres to the national standard GB/T6414-2017. For investment castings, select the following corresponding tolerance grades based on their maximum nominal size: 1. When the maximum nominal size is ≤100, select DCTG4~DCTG6 grade; ...

Measures to prevent oxide inclusions: Strictly control the smelting process, smelt rapidly, reduce oxidation, and thoroughly remove slag. Aluminum-magnesium alloys must be melted under a covering agent. The furnace body and tools should be clean, free of oxides, and preheated; paint should be dried after application. The designed casting system must have stable flow, buffering, and skimming capabilities. An inclined gating system should be used to ensure stable liquid flow and prevent secondary oxidation. The selected coating should have strong adhesion, and slag should form within the casting during pouring without peeling. Measures to prevent hot cracking: Local overheating should be avoided in the actual gating system to reduce internal stress. The mold and core slope must ensure the above 5°; inverted risers can be cored after solidification; sand cores can replace metal cores when necessary. Control the coating thickness to ensure consistent casting cooling rate. Select an appropriate mold temperature based on the casting thickness. Refine the alloy microstructure to improve hot cracking resistance. Improve the casting structure, eliminate sharp corners and abrupt changes in wall thickness, and reduce…

Because stainless steel casting cools and solidifies faster in a metal mold than in a sand mold, and the metal mold has no tolerance, the casting stress generated in the casting during metal mold casting is greater than that in sand casting, and the tendency for cracking is also greater. It is also easy to produce defects such as incomplete filling, cold shut, and white iron (for castings). Generally: (1) In order to prevent incomplete filling and cold shut in stainless steel casting, the following structural issues should be noted: A. The shape of the casting should be as streamlined as possible, avoiding sharp corners and abrupt changes in the connection structure, so as to facilitate the flow of molten metal; B. The wall thickness of the casting should be appropriate and not too thin, especially when the outline size of the casting is large; C. Large horizontal surfaces should be avoided, because they make the molten metal rise very slowly during casting, with a large surface area in contact with air, which is easy to oxidize. At the same time, because the metal mold dissipates heat quickly, the molten metal quickly loses its fluidity, which easily causes defects such as incomplete filling, cold shut, and inclusions; (2) In order to prevent stainless steel casting…

Stainless steel is an alloy steel with a chromium content of at least 10.51 TP3T. It possesses high corrosion resistance and wear resistance, excellent processing performance, and a beautiful, decorative surface after grinding and polishing. When stainless steel first became popular in my country, people often distinguished it solely by its rust-resistance and non-magnetic properties. However, this is inaccurate and vague. There are many types of stainless steel, each with different uses, and their rust resistance, corrosion resistance, and magnetic properties vary considerably. Simple surface characteristics are no longer sufficient for differentiation. Below, we list the characteristics and elemental composition of some commonly used stainless steel alloys, which are widely used in production and daily life. Common Stainless Steel Characteristics and Uses Alloy Grade Alloy Properties Application Areas 304 Austenitic stainless steel with a Ni content greater than 81 TP3T, food-grade alloy, suitable for general household and commercial use, safe for long-term human contact, and is the most widely used stainless steel…

Precision casting, also known as lost-wax casting, is a near-net-shape manufacturing process and currently the most advanced casting technology. Through precision casting, we can produce semi-finished or finished products with complex shapes, high dimensional accuracy, smooth surfaces, and shapes close to the final form of the part, which can be used directly without further processing or with minimal processing. The main production process of precision casting is as follows: First, a wax model with the same dimensions and shape as the product is made. Then, layers of refractory material are coated onto the surface of the wax model. After drying, a shell mold with sufficient strength is obtained. Then, the wax is melted and removed, and molten steel is poured into it. After cooling, a steel product identical to the wax model is obtained. Compared to ordinary machining, precision casting can minimize machining and achieve a high degree of detail. For some extremely complex parts, precision casting is often the only way to manufacture them. Haijin Company's precision casting process flow in Xinghua City Haijin Stainless Steel…