Currently, several commonly used precision casting methods in factories can meet actual production needs. However, the performance indicators of the mold material are directly related to the quality of the precision castings, directly affecting their dimensional accuracy and quality. Therefore, higher requirements must be placed on the dimensional and quality control of mold material castings. The performance requirements for mold materials are as follows: 1. A small linear shrinkage rate and a minimum coefficient of expansion within the softening temperature range are necessary to achieve the required dimensional accuracy. 2. Low heat capacity and a moderate melting point are required to facilitate the creation of the mold shell using wax and the removal of the wax from the shell. 3. The mold material should have sufficient hardness and strength at room temperature and high thermal stability at slightly above room temperature to prevent various cracks, breaks, or surface scratches in actual production and daily life. 4. Low viscosity in the molten state is required to provide good flowability and molding performance, which is beneficial for thin-walled and complex-shaped castings…

Precision machining is an essential process for manufacturing large and small parts according to strict manufacturing specifications and critical tolerances. Of course, not every job requires this level of precision, but it is crucial when parts need to meet highly specific design specifications. Precision castings are ubiquitous, from medical and aerospace to automotive and home entertainment. Understanding precision machining: The basic form of precision machining is taking a larger piece of material and cutting away the excess to produce a smaller piece. A material removal process replaces the larger piece of material in a certain way. This smaller piece of material will be precisely where it is needed to successfully complete its task. Typically, it involves cutting the material to precise shapes and dimensions, thus requiring the use of multiple machines. &…

The Necessity of Quality Inspection for Large and Medium-Sized Stainless Steel Castings: In recent years, the rapid development of the casting industry has led to the problem of inconsistent product quality. However, if we manufacture a product and immediately sell it without considering its quality, the product quality is insufficient, and customers will feel uneasy using it. This principle also applies to large and medium-sized stainless steel castings. It's not necessary to investigate the reasons for the substandard large and medium-sized stainless steel castings or complete the process during manufacturing; the goal is to continuously improve product quality to enhance overall usability. Naturally, this involves continuously improving the advantages of the product's specific characteristics based on its application capabilities, aiming at all aspects of the product's application effects, so that the quality of large and medium-sized stainless steel castings, such as at the top level, has excellent quality control, reflecting the advantages of the product's overall characteristics, and making it competitive. So how exactly do we…

This standard is based on the casting surface roughness comparison sample block specified in (GB/T 15056-2017) to inspect the casting surface roughness plating, and serves as a reference for casting process and selection of casting surface roughness.

Dimensional accuracy is one of the important quality indicators of castings. The dimensional tolerance standard for castings is the objective basis for measuring the dimensional accuracy of castings. Haijin Stainless Steel strictly adheres to the national standard GB/T6414-2017. For investment castings, the following corresponding tolerance grades are selected based on their maximum nominal size: 1. When the maximum nominal size ≤ 100, select DCTG4~DCTG6 grade; 2. When 100 < maximum nominal size ≤ 400, select DCTG4~DCTG8 grade; 3. When the maximum nominal size > 400, select DCTG4~DCTG9 grade. Casting dimensional tolerance (DCTG), casting straightness tolerance, casting flatness…

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…