Tungsten processing involves various processes and technologies to address its high melting point, high hardness, low-temperature brittleness, and other characteristics. The core processes include basic forming, precision machining, and surface strengthening.

1、 Basic molding process

1. Powder metallurgy

Raw material preparation: Using tungsten powder with a purity of ≥ 99.95%, it is sieved by ball milling and mixed with alloy elements such as nickel and iron to ensure a particle size of 5-10 μ m to optimize formability.

Forming technology:

Isostatic Pressure Forming (CIP): pressure ≥ 2500 MPa, suitable for large-sized or thick walled workpieces;

Compression molding: used for preliminary forming of small or complex structural blanks.

High temperature sintering: Sintering at a temperature greater than 2000 ℃ in a hydrogen or vacuum environment to achieve densification.

2. Plastic processing technology

Hot rolling/Warm rolling:

The billet temperature is 1350-1500 ℃, and the plate is rolled from 8mm to 0.5mm. The warm rolling further reduces the thickness to 0.2mm, and graphite lubrication and crack prevention need to be sprayed.

Spinning forging: Rotating forging in hydrogen gas at 1400-1600 ℃ to convert square billets into high-density round bars.

Drawing: Preheat to 100-350 ℃ and gradually draw to produce fine wires with a diameter of less than 0.06mm.

2、 Precision machining and cutting technology

1. Difficulties in mechanical processing

Tungsten has high hardness and brittleness, requiring specialized hard alloy cutting tools, combined with low-speed cutting and cooling lubrication processes to prevent tool wear and workpiece cracking.

2. Selection of cutting fluid

High speed steel cutting tools: oil-based cutting fluid for medium and low-speed cutting; Water based emulsion cooling for high-speed cutting or rough machining.

Hard alloy cutting tools: using oil-based cutting fluid and anti-wear additives, requiring high flow spray to prevent sudden thermal collapse at high speeds.

3、 Strengthening and surface treatment

1. Heat treatment process

Annealing: Maintain at 1250 ℃ to relieve stress and improve plasticity; Recrystallization annealing requires higher temperatures to achieve uniform microstructure.

Hardening treatment: Heating at 1050 ℃ and rapid cooling to increase hardness, but the risk of brittleness needs to be balanced.

2. Surface coating technology

Tungsten carbide coating: prepared by PVD/CVD process, with a hardness of HV1300, used for wear-resistant cutting tools and aviation components.

Electroplating protection: Tungsten alloy electroplating replaces traditional chrome plating, with better corrosion resistance and environmental friendliness, suitable for oil drilling equipment.

4、 Special processes and cutting-edge technologies

1. Additive Manufacturing (PEP Technology)

Combining 3D printing and powder metallurgy: printing tungsten alloy blanks first, followed by degreasing and sintering to solve complex structural forming problems (such as irregular nuclear energy components).

2. Spark Plasma Sintering (SPS)

Pulse current+pressure coupling, rapid densification at<2000 ℃, grain size<300nm, improved creep resistance.

Summary: Tungsten processing requires the comprehensive application of multidisciplinary technologies, overcoming inherent material defects through process innovation, and meeting high-performance requirements in aerospace, military, semiconductor and other fields.