Description

1. Material selection and application

Ductile iron is chosen as the material, and its comprehensive performance close to steel. It is 30%~100% stronger than gray cast iron and has plasticity (elongation 5%~18%). It is 2 to 3 times more shock-absorbing than steel, which is suitable for motor vibration conditions.

2. Production process

(1) Smelting and spheroidizing: Add pig iron, scrap steel, recycled materials and other raw materials according to the proportion. Add spheroidizing agent, and carry out Primary Inoculation and Late Inoculation.

(2) Molding: Use resin sand or lost foam mold, and place chromite sand or chilled iron in key locations (such as bearing seats) .

(3) Pouring: bottom pouring, reducing oxidation slag inclusions; strictly control the casting temperature, speed and the cooling temperature when unpacking to avoid white spots.

(4) Sand removal and cleaning.

(5) Heat treatment : Heat treatment is carried out according to different materials and requirements to improve the hardness, strength and wear-resistance.

3. Quality Control

(1) Material control

Raw materials are added strictly according to the ratio; and before each batch of casting, the composition is tested by spectral analysis.

(2) Melting and pouring

Strictly control the spheroidizing temperature and pouring temperature. Carry out double-stage inoculation.

(3)Monitoring and test

I. Heat treatment chart record: furnace front analyzer; infrared temperature measurement, temperature monitoring during the entire pouring process.

II. NDT: UT, MT

III. Appearance inspection: no cold shut, cracks, or sand (visual inspection& penetration inspection)

(4) Pre-delivery inspection

I. Full-Dimensional inspection

II. Dynamic balancing test (high-speed motor)

III. Pressure test