High Temperature And Wear Resistance Stellite Cobalt-Chromium Alloy Blank

1 PRODUCT

Wear resistant copper alloy is a kind of wear-resistant alloy based on copper, which can be divided into bronze and brass. Because of its good thermal conductivity, conductivity and corrosion resistance, it is widely used in friction system, especially in conductive devices. Brass and bronze have the same use, mainly used as gear (worm gear), bearing bush, sleeve and other wear-resistant parts.

Beryllium bronze (beryllium 2%) with high copper content in bronze is the best wear-resistant copper alloy. Due to its good hardness, fatigue strength and corrosion resistance, it is used as bearing and precision gear material at high speed and high temperature (~ 300 ℃).

The properties of tin bronze and aluminum bronze are changed by adding a small amount of other elements, such as Fe, Ni, Zn, Mn, P, etc. In addition to the solid solution strengthening phase, they also contain some hard intermetallic compounds, which have high wear resistance, and are commonly used to make Babbitt alloy bushing.

Tin (al, Mn, Pb or SI) brass can be formed by adding Sn, Al, Mn, Pb or Si elements into brass under the condition of keeping its mechanical and technological properties basically unchanged. These elements have obvious effect on improving the corrosion resistance, wear resistance and friction reducing properties of the alloy.

Products: Forgings, bars, wires, plates, belts, tubes, machined products

Conventional grades: AMPCO? 8, AMPCO? 15, AMPCO? 18, AMPCO? 21, AMPCO? 22, AMPCO? 25, AMPCO? 642, AMPCO? M4 etc

2 EQUIVALENT DESIGNATION

UNS S44004, X105CrMo17, W.Nr.1.4125, SUS 440C, 9Cr18Mo, 102Cr17Mo, SAE 51440C

3 OVERVIEW

AISI 440C stainless is a martensitic stainless steel with high carbon and chromium content and designed to provide stainless properties with maximum hardness. It has been used primarily as a bearing steel, and is used in the hardened plus tempered condition. When heat-treated, 440C stainless attains the highest hardness of any stainless steel (about Rockwell C 60).

After heat treatment, it is capable of attaining the highest strength, hardness and wear resistance of all stainless alloys. Compared to austenitic grades, 440C has moderate corrosion resistance, comparable to 304. This grade of stainless steel plate can be hardened through heat treatment, but machining is preferable in the annealed condition and becomes extremely difficult once hardened.

Highest resistance can be achieved through hardening and polishing, and the properties of 440C steel make it ideal for knife blades and cutting instruments like surgical blades. This grade, once hardened, hold a sharp edge and resists corrosion, and can be polished to a near mirror finish. Its toughness and ability to resist wear makes 440C stainless steel a good choice for tools like chisels and ball bearings.

4 Advantage

(1) World class top quality

(2) Ultra high pure (For example Oxygen lower than 8ppm)

     Ultra-high purity smelting process VIM + IG-ESR + VAR

(3) Ultra-high strength (For example yield strength more than 1400MPa)

5 Key application

For high-end equipment with demanding core components such as aircraft wing wave generator which request ultra high purity and ultra high strength under harsh working condition.

Above test report for reference.

6 CHEMICAL COMPOSITION (wt%):

7 PHYSICAL PROPERTY

Density: 7.62 g/cm³ (0.275lb/in³)

Mean specific heat 32 to 212°F: 0.11 Btu/lb/°F

Mean coefficient of thermal expansion 32 to 212°F: 5.60 x 10^-6 in/in/°F

Thermal conductivity: 212°F, 168.0 BTU-in/hr/ft²/°F

Modulus of elasticity 29.0 x 10³ ksi

Electrical resistivity70°F: 361.0 ohm-cir-mil/ft

8 CORROSION RESISTANCE

Stainless steel 440C resists corrosion in normal domestic environments and very mild industrial environments, including many petroleum products and organic materials.

This grade is used in the hardened plus tempered condition. Optimum corrosion resistance is obtained by hardening from 2000ºF (1093ºC) to ensure better carbide solution.

However, care should be taken to minimize time at 2000ºF (1093ºC) to avoid excessive grain coarsening. For best corrosion resistance, the tempering temperature should be below about 800ºF (427ºC).

For optimum corrosion resistance, surfaces must be free of scale, lubricants, foreign particles, and coatings applied for drawing and heading. After fabrication of parts, cleaning and/or passivation should be considered.

9 MECHANICAL PROPERTIES

Typical room temperature mechanical properties

Hardned 1900°F(1038°C), oil quench, tempered 600°F(316°C)

Typical hardness

1” (25.4mm) round, hardened 1900°F (1038°C), oil quench, and tempered one hour.

For optimum corrosion resistance, do not temper above 800°F (427°C)

10 MACHINING AND FORMING

Hot working

This steel should be handled like high-speed tool steel. Preheat to 1400/1500ºF (760/816ºC), then heat slowly and uniformly to 1900/2100ºF (1038/1149ºC). Do not forge below 1700ºF (927ºC), and reheat as often as necessary. Cool in a furnace if possible or in warm dry lime or ashes. Anneal after forging; cool to room temperature before annealing.

Cold working

If annealed for maximum softness, this steel can be moderately cold formed or headed.

Machinability

For most machining operations, this steel cuts best when in the dead soft annealed condition. Because of its high carbon content it machines somewhat like high-speed steel. Because chips are tough and stringy, chip curlers and breakers are important.

11 HEAT TREATMENT

Annealing

For maximum softness, this steel should be heated uniformly to 1550/1600ºF (843/871ºC). Soak and cool very slowly in the furnace. Brinell hardness approximately 223. Intermediate or process annealing treatment-heat uniformly to 1350/1400ºF (732/760ºC). Air cool. Brinell hardness about 255.

Hardening

Heat to 1850/1950ºF (1010/1066ºC); soak; quench in warm oil or cool in air. Do not overheat. When overheated, full hardness cannot be obtained. See comments under corrosion resistance.

Tempering

Hardness of approximately Rockwell C 60 will be obtained. To remove peak stresses and yet retain maximum hardness, temper at least one hour at 300/350ºF (149/177ºC).

12 BUSINESS TERM