n order to solve the difficulties of MIM technology and promote the practical application of MIM technology, an advanced powder engineering program was developed in the United States in the mid-1980s, covering 18 subjects related to injection molding.Subsequently, Japan and Germany also actively carried out the development and research of MIM.

In addition, due to the aerospace and aircraft engine (commercial and military) market demand to pick up, the hot isostatic pressing industry companies in 2016 also grew. Demand for compact services for metal injection molding and metal based manufacturing is still strong and will continue to grow.

Mechanical parts, such as shafts, gears, bearings, blades, springs, etc., periodically change the stress at each point during the working process. The stress that changes periodically with time is called alternating stress (also called cycle). stress).

316L stainless steel has good welding properties. All standard welding methods can be used for welding. When welding, 316Cb, 316L or 309Cb stainless steel filler rods or welding rods can be used for welding according to the application. For best corrosion resistance, the welded section of 316 stainless steel requires post-weld annealing. If 316L stainless steel is used, post-weld annealing is not required.

This process technology is suitable for the mass production of small, precise, three-dimensional shapes and metal parts with special performance requirements.

Inside of the insulation layer is a multi-layer graphite felt with high performance, and the surface is CFC material. The input of process gas can be adjusted independently and the flow rate can be controlled, which helps to maintain a differential pressure in the heat zone and in the gap between distributor and furnace shell. The uniform process gas circulates inside and outside the hot zone to ensure the uniform evaporation of the binder, prevent the re-deposition of the binder, and protect the hot zone from pollution.

About 60% of MIM materials is stainless steel, the most common alloy is 17-4PH and 304L and 316L austenitic stainless steel. Off-the-shelf injection raw materials cost $30-50 (about 184-307 yuan (RMB)/kg). After forming and degreasing, the original parts can be worth more than thousands of dollars. In this way, the key components of vacuum sintering furnace are very important.

An important factor that vacuum sintering furnace can save cost is its economical process gas and power consumption. According to different gas types, these two cost elements can account for 50% of the total cost in sintering process.

However, some professional vacuum furnaces with the above technical advantages are limited by small available capacity. Their disadvantage in input-output ratio and low energy utilization may offset the cost savings in other MIM process steps.

The MIM materials(powder and fed stock) shipment is 6000--7000 tons. In 2018, 3000--3500 tons were imported. About 8 MIM factories annual capacity is over 100 tons. Meanwhile, 9 MIM fed stock factories annual capacity is 800--1000 tons.

The weight of the products ranges from 0.1 to 250 grams, and 50 grams is the most economical weight. 0.01g products can also be produced now. Because of the price of raw powder, the cost of products that larger than 100g may be high. The wall thickness of 2 to 6 mm is the most suitable for MIM.

The causes of straightness overshoot are as follows: die straightness overshoot, uneven distribution of compact density, uneven wall thickness of compact, etc.

In the production of powder metallurgy parts, the higher the density of materials, the higher the physical and mechanical properties. In other words, the compact density and distribution of powder metallurgical parts will determine the performance of the final product.

Powder metallurgy gears are commonly used parts in automotive. Through one-time forming and finishing process, the requirement of gear accuracy can be achieved completely without other post-processing, and the processing efficiency can be effectively promoted.

The surface roughness (Ra) of_MIM sintered billet can reach 1 micron, and other beautiful appearance can be obtained by various surface treatments.

Germany's BASF company has made a great contribution to MIM turbocharger components. BASF company uses unique Catamold process to produce MIM turbocharger parts. The mechanical strength of MIM parts and precision casting samples were compared at room temperature. The results are shown in Table. This proves that excellent material properties can be obtained by Catamold process.

Low pressure casting is a process of filling the cavity with liquid metal under pressure to form castings. MIM is a kind of powder metallurgy. Solid powder particles are used in the process. During sintering, it does not need to make the metal reach the melting point. It has the advantages of complete melt, low energy consumption and high batch production efficiency. MIM products have no segregation and have better homogeneity than casting products. MIM materials can also be selected in a wide range, such as low alloy steel, stainless steel, superalloys, cemented carbides, titanium alloys and cermets.

Generally speaking, MIM can reproduce about 10 times the average particle size for micro parts, which is particularly suitable for micro parts. If smaller features are to be manufactured, smaller powders are needed. Now the available metal powder is 1 micron. Some powders are too active to reach the size range(e.g., Ti), while other metal powders are easier to produce (e.g., stainless steel) by special aerosol spraying.

In recent years, in order to manufacture metals and alloys that can be used for mass production of micro-parts and micro-structure surfaces, the MIM industry has developed micro-metal injection moulding process (mu-MIM). Mu-MIM greatly improves the micro-applications of metals and alloys, such as new materials with high temperature stability, strength and toughness, and thermal conductivity and magnetism.

Non-uniform degreasing in furnace A. The way of placing products needs to be adjusted. B. Check the temperature difference of the furnace and test the temperature. C. There is dead angle in the furnace. It is necessary to increase the rotational speed of circulating air.