1. Definition of malleable cast iron pipe fittings
Malleable iron pipe fittings are cast iron pipe fittings with high strength, plasticity and impact toughness, and are usually used in pipeline systems that require high mechanical properties. Malleable cast iron pipe fittings are high-strength and tough cast iron transformed from white cast iron through a specific heat treatment process. This material has good mechanical properties and can partially replace carbon steel. It is suitable for pipeline connections that require high strength and toughness.
2. Classification of malleable cast iron pipe fittings
Malleable cast iron pipe fittings are mainly divided into the following categories according to their metallographic structure and chemical composition:
① Black heart malleable cast iron: The matrix is ferrite, which has good plasticity and toughness.
② Pearlitic malleable cast iron: The matrix is pearlite, which has high strength and hardness.
③ White heart malleable cast iron: The outer layer is ferrite, with a small amount of pearlite and flocculent graphite remaining in the center, and has good weldability.
3. Material standards for malleable cast iron
①GB/T 9440-2010: Chinese national standard, which specifies the classification, grade, technical requirements, test methods, inspection rules, etc. of malleable cast iron parts. ②ISO 5922: International standard, which specifies the chemical composition, mechanical properties, metallographic structure, etc. of malleable cast iron. ③ASTM A197: American Society for Testing and Materials standard, which specifies the chemical and physical properties of malleable cast iron.
4. Design standards for malleable cast iron
①EN 10242: European standard, which specifies in detail the requirements for the design, size, tolerance, material, manufacturing and inspection of malleable cast iron threaded pipe fittings. ②BS 5163: British standard, which specifies the technical requirements and test methods for cast iron gate valves for water supply operated by special levers. ③ASME B16.3 American standard, which covers the design, manufacturing and acceptance requirements of malleable cast iron threaded fittings.
5. Thread standards for malleable cast iron
①ISO 7-1: International standard that specifies the dimensions, tolerances and markings of pipe threads for pressure-tight connections. ②BS British standard thread, specifies the dimensions, tolerances and markings of 55° sealing pipe threads. ③ American standard NPT thread, specifies the dimensions, tolerances and markings of 60° sealing pipe threads.
6. What products are included in malleable cast iron pipe fittings
Malletable cast iron pipe fittings are a type of pipe fittings widely used in pipeline systems, mainly used to transport fluids such as water, oil, air, gas, and steam. According to their structure and purpose, malleable cast iron pipe fittings include a variety of product types. The following are some common malleable cast iron pipe fittings products:
- Elbows: Purpose: used to change the direction of the pipeline. Type: 90 degrees, 45 degrees, 180 degrees, etc.
- Tees: Purpose: used for branch connection of pipelines. Type: straight tee, oblique tee, etc.
- Crosses: Purpose: used for cross connection of pipelines. Type: standard cross, oblique cross, etc.
- Couplings: Purpose: used for straight connection of pipelines. Type: short pipe straight, long pipe straight, etc.
- Reducers: Purpose: used to connect pipelines of different diameters. Type: concentric reducer, eccentric reducer, etc.
- Caps: Purpose: used to close the end of the pipe. Type: standard cap, neck cap, etc.
- Flanges: Purpose: used to connect and fix pipes. Type: flat welding flange, butt welding flange, etc.
- Check Valves: Purpose: to prevent fluid backflow. Type: lift check valve, swing check valve, etc.
- Safety Valves: Purpose: to release overpressure fluid and protect system safety. Type: spring-loaded safety valve, lever-loaded safety valve, etc.
- Unions: Purpose: used for quick connection and disassembly of pipes. Type: standard union, quick union, etc.
- Reducer Unions: Purpose: used to connect pipes of different diameters and provide quick connection and disassembly. Type: concentric reducer, eccentric reducer, etc.
- Threaded Fittings: Used for threaded connection of pipes. Types: internal threaded fittings, external threaded fittings, etc.
These products ensure the flexibility, reliability and safety of the pipeline system through their unique structure and function. Malleable cast iron pipe fittings are widely used in various industrial and civil fields due to their good mechanical properties and