Understand the key ASTM material specifications of valves. Cast valve bodies are made by injecting liquid metal into molds, which are usually used for valves with diameters greater than 2 inches. Forged valve body is forged from solid steel. The key specifications of cast steel valve body materials are: ASTM A2 16 of WCA, WCB and WCC, ASTM A352 of LCB/LCC at low temperature, and ASTM A35 1 of CF8/CF8M. Tma A105, A350 and A 182 cover the body materials of small (or high-pressure) forged valves.

Cast steel valve

First of all, let's clarify the difference between cast and forged valves, although it seems obvious: cast valves have cast valve bodies and forged valves have forged valve bodies! The difference lies in the material construction process of valve body, that is, steel forging or casting.

Now let's look at the key materials of casting valve body: WCB WCA ASTM A2 16, WCC (carbon steel at high temperature).

ASTM A2 16 specification covers three grades of carbon steel (WCA, WCB and WCC), and their characteristics are slightly different in chemical and mechanical properties. The brands of these cast valve bodies match A53, A 106 and API 5L carbon steel pipes.

The surface of steel castings should be free of attached elements, such as sand, cracks, hot cracks and other defects.

Note: Compared with

For every reduction of 0.0 1%, which is lower than the specified large carbon content, manganese is allowed to exceed the specified large value by 0.04%, and the higher value can reach 1. 10%.

For every reduction of 0.0 1%, which is lower than the specified large carbon content, it is allowed to be 0.04%Mn higher than the specified large value, and the higher value can reach 1.28%.

For every reduction of 0.0 1%, which is lower than the specified larger carbon content, manganese is allowed to exceed the specified larger value by 0.04%, and the higher value is 1.40%.

LCB Tm352/LCC (low temperature carbon steel)

The specification of patent TM A352 covers all kinds of low-temperature carbon steels (called LCA, LCB, LCC, LC 1, LC2, LC3, LC4, LC9, CA6NM) used for cast steel valves, flanges, pipe fittings and other pressure-bearing parts.

Octoma A351CF8/CF8m (stainless steel)

ASTM A35 1 Specification includes austenitic steel castings for valves, flanges, joints and other pressure-bearing parts.

The most common grades are ASTM A35 1 CF3, CF8(SS304) and CF8M(SS3 16).

Steel should be smelted by electric furnace, with or without separate refining, such as argon-oxygen decarbonization.

Any ASTM A35 1 casting shall be heat treated and then quenched or rapidly cooled in water. Steel shall meet the chemical and mechanical requirements specified in the specification.

Precautions:

The niobium content of CF8C grade should be 8 times higher than that of carbon, but not more than 1.00%.

The niobium content of CF 10MC grade should be 10 times higher than that of carbon, but not more than 1.20%.