KV-1 MIM Parts

Introduction of KV-1 Metal Injection Molding Parts

4J29 alloy is also known as Kovar alloy. The alloy has a linear expansion coefficient similar to that of borosilicate hard glass at 20-450°C, a higher Curie point, and good low-temperature microstructure stability.

Comparison table of the same foreign brands

Qinhuangdao Zhongwei Precision Machinery Co., Ltd. is a collection of copper alloy metal injection molding, iron-based metal injection molding, stainless steel-based metal injection molding, aluminum alloy metal injection molding, nickel alloy metal injection molding, cobalt alloy metal injection molding, tungsten alloy metal injection molding A comprehensive high-tech enterprise integrating R&D, production and sales of injection molding, cemented carbide metal injection molding, and powder metallurgy structural parts.

Product Introduction

1. Implementation standards: the company strictly implements ISO9001, ISO14001, IATF16949 certification, and products have passed ROHS, FDA EU certification, etc.

2. KV-1 MIM Parts material standard: ISO, GB, ASTM, SAE, EN, DIN, BS, AMS, JIS, ASME, DMS, TOCT, GB

3. Main processes: metal injection molding MIM, powder metallurgy PM, investment casting, die-casting aluminum,

4. Available materials for powder metallurgy:

Copper alloys, iron bases, titanium alloys, stainless steel bases, aluminum alloys, nickel alloys, cobalt alloys, tungsten alloys, cemented carbides, hydroxy alloys, soft magnetic materials and 3D printing can be customized according to customer requirements.

Product Description

4J29 alloy is also known as Kovar alloy. The alloy has a linear expansion coefficient similar to that of borosilicate hard glass at 20-450°C, a higher Curie point, and good low-temperature microstructure stability. The oxide film of the alloy is dense and can be well wetted by glass. It does not interact with mercury, and is suitable for use in meters containing mercury discharge. It is the main sealing structure material of electric vacuum devices.

●Similar grades

Russia USA UK Japan France Germany

29HК Kovar Nilo K KV-1 Dilver P0 Vacon 12

29HК-BИ Rodar KV-2

Techallony Glasseal 29-17 Telcaseal KV-3 Dilver P1 Silvar 48

●Technical standard

YB/T 5231-1993 "Technical conditions for iron-nickel-cobalt glass sealing alloys 4J29 and 4J44"

●Chemical composition

C≤0.03% Mn≤0.50% Si≤0.30% P≤0.020% S≤0.020% Cu≤0.20% Cr≤0.20% Mo≤0.20%

Ni=28.5～29.5% Co=16.8～17.8%

Fe = surplus

Under the condition that the average linear expansion coefficient reaches the standard, the content of nickel and cobalt is allowed to deviate from the range specified in Table 1-2. The content of aluminum, magnesium, zirconium and titanium should not exceed 0.10% each, and the total amount should not exceed 0.20%.

●Heat treatment regime

The performance test samples for the expansion coefficient and low temperature microstructure stability specified in the standard are heated to 900℃±20℃ in a hydrogen atmosphere, kept for 1h, then heated to 1100℃±20℃, and kept for 15min, at a temperature not greater than 5℃/min The speed is cooled to below 200 ℃.

●Application overview

The alloy is a typical Fe-Ni-Co hard glass sealing alloy commonly used in the world. It has been used for a long time in the aviation factory with stable performance. It is mainly used for glass sealing of electric vacuum components such as launch tubes, oscillator tubes, ignition tubes, magnetrons, transistors, sealed plugs, relays, integrated circuit lead wires, chassis, shells, brackets, etc. In the application, the selected glass should be matched with the expansion coefficient of the alloy. Strictly test its low temperature tissue stability according to the use temperature. Appropriate heat treatment should be carried out during processing to ensure that the material has good deep drawing properties. When using forgings, their air tightness should be strictly checked.

●Organizational structure

After the alloy is treated according to the heat treatment system specified in 1.5, and then frozen at -78.5 ℃, martensitic structure should not appear for more than or equal to 4h. However, when the alloy composition is not appropriate, different degrees of austenite (γ) to acicular martensite (α) transformation will occur at room temperature or low temperature, and the transformation will be accompanied by volume expansion. The expansion coefficient of the alloy increases accordingly, resulting in a sharp increase in the internal stress of the sealing part, and even partial damage. The main factor affecting the low temperature microstructure stability of the alloy is the chemical composition of the alloy. It can be seen from the Fe-Ni-Co ternary phase diagram that nickel is the main element to stabilize the γ phase, and a high nickel content is conducive to the stability of the γ phase. As the total deformation rate of the alloy increases, its microstructure tends to be more stable. Alloy composition segregation may also cause localized γ→α transformation. In addition, the coarse grains will also promote the γ→α transformation.

●Introduction to 4J29 production process

The production process of 4J29 Kovar alloy is generally smelting - hot working - forging, hot rolling - cold working (rolling) - intermediate annealing - cold working - finished heat treatment (annealing). 4J29 smelting usually adopts non-vacuum induction furnace or electric arc furnace. The carbon content of 4J29 is generally controlled at about 0.02%, and the content of gas and impurities in the steel should be minimized to prevent bubbles from appearing when the ingot is expanded and sealed after 4J29 is smelted. When 4J29 is forged and hot rolled, it is generally used to start forging at 1150~1200 degrees Celsius, and the stop forging temperature is greater than or equal to 800 degrees Celsius. When 4J29 is cold rolled, the total deformation rate of each cold rolling shall not exceed 65% to prevent the formation of cold rolled fabrics and recrystallized fabrics during recrystallization annealing. 4J29 recrystallization annealing temperature is generally 850~900 degrees Celsius.

●4J29 application

4J29 Kovar alloy is used for electric vacuum, mainly used for sealing with hard glass (DM-308), 4J29 can also be sealed with 95% AL2O3 ceramics. 4J29 is the main sealing structure material for electric vacuum devices.

●4J29 order

4J29 Kovar Alloy Convention Co., Ltd. will review the drawings and make quotations. The development department of the research institute can also organize the production of 4J29 materials according to the working conditions of different customers. Mold deadline and product delivery time

●4J29 Kovar alloy delivery form

4J29 round steel. 4J29 sheet. 4J29 steel strip. 4J29 thick plate. 4J29 forgings. Metal injection molding MIM custom service.

Kovar alloy 4J29 is one of the most mature products of Qinhuangdao Zhongwei Precision Machinery Co., Ltd. It is also a nickel-cobalt alloy product with a large investment in scientific research.

1. Overview of Kovar Alloy 4J29.

Kovar 4J29 is a nickel-cobalt alloy containing 29% Ni.17% Co and the balance Fe. In a wide temperature range (-80~450°C), the thermal expansion curve is consistent with some high silicon borosilicate hard glasses. Widely used in the manufacture of high vacuum glass-to-metal hermetic seals. Because 4J29 has good sealing, welding and processing properties, this alloy has been widely used in various countries. It is generally called kovar in foreign countries.

Heat treatment process of 4J29 Kovar alloy.

4J29 alloy intermediate heat treatment.

When Kovar alloy 4J29 is cold rolled, cold drawn and cold stamped, in order to eliminate the hardening caused by processing and restore its necessary plasticity, it is beneficial to continue processing. Temperature: 750°C~900°C; Holding Time: Determined according to the size and quantity of 4J29 material. Generally 1~2 hours; Atmosphere: Protect the atmosphere, dry hydrogen (dew point -40°C or so). Dispersed ammonia or vacuum; cooling method: furnace cooling or furnace cooling and air cooling.

2.4J29 Kovar alloy finished product final heat treatment.

After the 4J29 part is formed, it is necessary to remove the gas or surface carbon and grease before sealing with the glass, and at the same time eliminate the residual machining stress in the 4J29 part.

Temperature: 950~1050°C; Holding time: about 15 minutes; Atmosphere: warm hydrogen.

3. Kovar alloy 4J29 pre-oxidation system before sealing.

Heat to 800°C in air for 15 minutes or below 900°C for 5 minutes. Couldn't restore the atmosphere.

6. Welding Kovar Alloy 4J29.

4J29 alloy has good welding performance, easy to arc welding, resistance welding and brazing. When 4J29 arc welding, Ni-Cr stainless steel (such as 18cr-8ni or 25cr-12ni, etc.) can be used as the electrode. If Kovar 4J29 is joined to mild steel, it is best to weld with atomic hydrogen.