White Cast Iron

Product details

Qinhuangdao Zhongwei Precision Machinery Co., Ltd. is a leading casting enterprise in Qinhuangdao. Our company is equipped with advanced product manufacturing technology and testing methods, pre-furnace analyzer, post-furnace testing equipment, and spectrometer imported from Germany to more accurately analyze the chemical composition and physical properties of castings. Main production: ordinary white cast iron, low alloy white cast iron, medium alloy white cast iron, high alloy white cast iron and other accessories.

Classification of white cast iron castings

1. White cast iron

White cast iron usually contains 2.0%~3.6%C, 0.5%~1.9%Si, 0.25%~0.8%Mn, 0.06%~0.2%S, 0.06%~0.2%P, and the rest is Fe. White cast iron can be made by adding alloying elements Cr, Mo, Cu, Al, etc. During solidification, according to the Fe-Fe3C phase diagram, no graphite is precipitated. Except for a small amount of carbon dissolved in ferrite, most of the carbon exists in the cast iron in the form of cementite. The microstructure is determined by the chemical composition and cooling rate. When the cooling rate is large enough, the microstructure is white cast iron. With the decrease of cooling rate, the microstructure of cast iron changes to hemp cast iron, pearlitic gray cast iron, pearlitic ferritic gray cast iron and ferritic gray cast iron. White cast iron contains a lot of free carbides, with high hardness, HB above 500, and poor toughness. In the production of iron castings, it is required to avoid pitting or white mouths. White cast iron is only used to make wear-resistant farm implements, grinding balls, blades, pumps, rollers, etc. Mainly used for the production of malleable cast iron and as a raw material for steelmaking.

2. Ordinary white cast iron

As early as the Spring and Autumn Period, China made white cast iron with good wear resistance and used it as some anti-wear parts. This cast iron has the characteristics of high carbon and low silicon, high hardness, but very brittle, suitable for manufacturing parts with small impact load, generally used in ploughshares, grinding discs, guide plates, etc. Heat treatment is often used in production to improve its performance and expand its application range. Carbon plays the most important role in the wear resistance of ordinary white cast iron. The higher the carbon content, the more cementite is formed, forming a large amount of ledeburite, so the higher the hardness, the better the wear resistance. . However, the higher the carbon content, the lower the toughness. The quantity and distribution of cementite should be selected according to the specific working conditions of the part. Usually, the hardness of ordinary white cast iron has a linear relationship with the carbon content, that is, HS=16.7C+13 (HS—Shore hardness; C—Carbon content percentage).

3. Low alloy white cast iron

Adding a small amount of alloying elements to ordinary white cast iron can improve the microhardness of carbides and strengthen the metal matrix, thereby improving wear resistance. White cast iron containing chromium, molybdenum, copper and other elements is usually smelted in a cupola, and most of them are used in the as-cast state, so the cost is low. However, the carbides in the metallographic structure of this white cast iron are still continuous network, so the brittleness is still relatively large, and it is suitable for occasions where the requirements for wear resistance and toughness are not too high. Adding 0.15% to 0.55% of boron, the boron mainly enters the carbide, which can also improve the wear resistance.

4. Medium alloy white cast iron

With chromium as the main alloying element, when the amount of chromium added reaches 9%, (Cr, Fe) 7C3 carbide appears in the structure, and its hardness is as high as 1300-1800HV. This carbide is in the form of an isolated rod or plate, with poor continuity, so it has good toughness and high strength. In addition to chrome, medium alloy white cast iron also has:

(1) Nickel hard white cast iron, the grades of International Nickel Company are Ni-Hard 1, 2, 3, and 4. The nickel content is mostly between 3% and 5%, and the chromium content can be divided into two types: 2% Cr and 9% Cr. The former carbide is (Fe, Cr) 3C, with a hardness of 1100-1150HV, which is 900-1000HV higher than that of Fe3C. The latter is mostly (Cr, Fe) 7C3 with higher hardness. Ni-Hard1, 2, and 3 all contain 2% Cr. The difference is mainly due to the difference in carbon content. High carbon has good wear resistance and poor toughness; low carbon is the opposite. International Nickel Corporation also has two special materials: high carbon Ni-Hard4, which has high wear resistance and low impact fatigue life; another boron-containing Ni-Hard1, with a boron content of 0.25% to 1.0%, Boron can increase the hardness of the martensitic matrix up to 1000HV, and this material is used for castings with relatively simple shock loads.

(2) Manganese white cast iron has a high manganese content that inhibits pearlite and stabilizes austenite. A certain amount of martensite appears in the structure, but there is more retained austenite. The manganese content of this cast iron is 5% to 8%, and the cost is low, but the wear resistance is low and the casting performance is also poor.

(3) Manganese-tungsten white cast iron, China manganese-tungsten No. 1 wear-resistant cast iron is used for parts that require machining; manganese-tungsten No. 2 wear-resistant cast iron has higher hardness. Usually both are used in the as-cast state.

(4) Tungsten-chromium white cast iron, there are three grades of W5Cr4, W9Cr6 and W16Cr2 in China, which are mainly used for occasions with large impact load, low-stress erosion abrasive wear and high-stress grinding abrasive wear. Applications are limited due to the high price of tungsten.

(5) Medium-chromium white cast iron, Ni-Hard4 is a medium-chromium white cast iron, which needs to add a lot of precious nickel. In order to save, the same purpose can be achieved by using copper, molybdenum and manganese combined alloying. Its mechanical properties are similar to Ni-Hard4.

5. High alloy white cast iron

The most widely used is high-chromium white cast iron with a chromium content of 12% to 20%, which forms (Cr, Fe) 7C3 carbides in the structure. High-chromium white cast iron is usually subjected to high-temperature heat treatment to precipitate secondary carbides, and austenite transforms into martensite when cooled. High-chromium white cast iron is widely used in dry grinding, such as iron-making blast furnace charge cups and chute liners. American Climax Molybdenum Company has two grades: 15-3 (containing 15% Cr-3% Mo) and 15-2-1 (containing 15% Cr-2 %Mo-1% Cu). 15-3 is divided into ultra-high carbon, high carbon, medium carbon and low carbon according to the level of carbon content. Low carbon has good toughness and low hardness, which is suitable for occasions with relatively large impact load; high carbon is used for occasions with small impact load, showing good wear resistance.

Product Description

1. Implementation standards: The company strictly implements ISO9001 & TS 16949 certification.

2. Product material standards: ISO, GB, ASTM, SAE, ISO, EN, DIN, JIS, BS

3. Main processes: sand casting, silica sol investment casting, water glass investment casting, shell casting, deburring, sand blasting, machining, heat treatment, leak testing, surface treatment, etc.

4. Available materials:

Gray iron: ISO standard: 100, 150, 200, 250, 300, 350

Ductile iron: ISO standard: 400-18, 450-10, 500-7, 600-3, 700-2, 800-2

—Other materials: cast iron, cast steel, cast aluminum, cast copper, alloy steel, etc. can be customized according to customer requirements.

According to the country, please check the corresponding national material grade in the table.

5. Available software: Pro/E, Auto CAD, Solidwork.

6. 2D & 3D drawings (Igs, PDF, JPEG, DWG, CAXA, UG, Stp...etc) can also be made according to samples.

7. Production process: sand casting, lost foam casting, water glass lost wax casting, silica sol investment casting, etc.

8. Product weight range: from 0.01kg to 2000kg;

Process Flow

1. Heat treatment: annealing, carbonization, tempering, quenching, normalizing, surface tempering

2. Processing equipment: CNC, WEDM, lathe, milling machine, drilling machine, grinder, etc.;

3. Surface treatment: powder spraying, chrome plating, painting, sandblasting, nickel plating, galvanizing, blackening, polishing, bluing, etc.

Moulds and Inspection Fixtures

1. Mold service life: usually semi-permanent. (except for lost foam)

2. Mold delivery time: 10-25 days, (according to product structure and product size).

3. Tooling and mold maintenance: Zhongwei is responsible for precision parts.

Available Materials List:

Grey iron and ductile iron

Other materials: cast iron, cast steel, cast aluminum, cast copper, alloy steel, etc. can be customized according to customer requirements.

Quality Control

1. Quality control: the defective rate is less than 0.1%.

2. Samples and trial run will be 100% inspected during production and before shipment, sample inspection for mass production according to ISDO standards or customer requirements

3. Testing equipment: flaw detection, spectrum analyzer, golden image analyzer, three-coordinate measuring machine, hardness testing equipment, tensile testing machine;

4. Provide after-sales service.

5. The quality can be traced back.

Scope of Application

1. Engine parts

2. Auto parts

3. Mechanical parts

4. Railway train parts

5. Truck parts

6. Tractor accessories

7. Construction equipment

8. Agricultural equipment

9. Other industrial fields

http://www.zw-metalware.com/