What kind of steel is generally used for industrial valves?

Common oilfield power plant industrial valves First of all, when selecting the main parts of the valve, the physical properties (temperature, pressure) and chemistry (corrosion) of the working medium should be considered first. At the same time, the cleanliness of the medium (with or without solid particles) should also be known. In addition, many kinds of materials can meet the requirements of the valve in many different working conditions. However, the most economical service life and the best performance of the valve can be obtained by choosing the valve material correctly and reasonably. There are many kinds of materials for valves, which are suitable for various working conditions. The commonly used shell materials, internal parts materials and sealing materials are introduced as follows.

Production of industrial valves in Shanghai Oilfield Power Plant

1 Commonly used materials for shells 1 . Gray cast iron is suitable for low-pressure valves with working temperature between -15 and 200°C and nominal pressure PⅣ≤1.6MPa. The medium used is water, gas, etc.

2. Black heart malleable cast iron Suitable for working temperature between -15～300℃. Medium pressure valve with nominal pressure PⅣ≤2.5MPa. The applicable medium is water, sea water, gas, ammonia, etc.

3. Ductile iron is suitable for working temperatures between -30 and 350°C. Medium and low pressure valves with nominal pressure PⅣ≤4.0MPa. Applicable media are water, sea water, steam, air, gas, oil, etc.

4. Carbon steel (WCA, WCB, WCC) is suitable for medium and high pressure valves with an operating temperature between -29 and 425°C. Medium 1 6Mn and 30Mn have a working temperature between -40 and 450°C and are often used to replace ASTM A105. Applicable medium is saturated Z-2: and superheated steam. High and low temperature oil, liquefied gas, compressed air, water, natural gas, etc.

5. Low-temperature carbon steel (1CB) is suitable for low-temperature valves with operating temperatures between -46 and 345°C.

6. Alloy steel WC6 and WC9 are suitable for high temperature and high pressure of non-corrosive medium with working temperature between -29 and 595°C C5 and C1 2 are suitable for high temperature and high pressure of corrosive medium with working temperature between -29 and 650°C valve.

7. Austenitic stainless steel is suitable for valves with working temperature between -196～600℃ and corrosive media.

8. Monel alloy is mainly suitable for valves containing hydrofluoric acid medium.

9. Hastelloy Mainly suitable for valves with strong corrosive media such as dilute sulfuric acid.

10. Titanium alloy is mainly suitable for valves of various strong corrosive media.

11. Cast copper alloy is mainly suitable for valves used in oxygen pipelines and seawater pipelines with working temperatures between -27 and 200°C.

12. Plastics and ceramics are both non-metallic materials.

The biggest feature of non-metal material valves is strong corrosion resistance and even has advantages that metal material valves cannot possess. - Generally suitable for corrosive media with nominal pressure N≤1.6MPa and working temperature not exceeding 60°C. Non-toxic plastic valves are also suitable for water supply industry. 2 Commonly used materials for valve trims The commonly used materials and service temperature ranges for valve trims are shown in Table 2-6. Also refer to JB/T5300-1995. Valve trim material lower temperature limit/C(.F) upper temperature limit/C(.F) valve trim material lower temperature limit/℃(F) upper temperature limit/℃(.F) 304 stainless steel 316 stainless steel bronze Inconel K Monel Monel Hastelloy B Hastelloy C Titanium Alloy No. 20 Alloy 416 Stainless Steel 40RC -268(-450) -268(-450) -273(-460) -240(-400) -240(-400) -240(-400) -198(-325) -198(-325) -29(-20) -198(-325) -46 (-50) -29(-20) 316(600) 316(600) 232(450) 649(1200) 482(900) 482(900) 371(700) 538(1000) 316(600) 316(600) 316(600) 427(800)440 Type Stainless Steel 60RC 17-4PH Alloy No. 6 (C0-Cr) Electroless Nickel Plating Chrome Plating Nitrile Rubber Viton Rubber PTFE Nylon Polyethylene Neoprene -29(-20) -40 (-40) -273(-460) -268(-450) -273(-460) -40(-40) -23(-10) -268(-450) -73(-100) -73(- 100) -40 (-40) 427 (800) 427 (800) 816 (1500) 427 (800) 316 (600) 93 (200) 204 (400) 232 ( 180) 3 Commonly used materials and applicable media for valve sealing surfaces Commonly used materials for valve sealing surfaces, applicable media and allowable temperature ranges are shown in Table 2-7. Table 2-7 Common materials and applicable media for valve sealing surface Materials for sealing surface Operating temperature c Hardness Applicable media Bronze -273～232 Water, sea water, air, oxygen, saturated steam, etc. 316L-268～316 14HRC Steam, water, oil, Gas, liquefied gas, and other slightly corrosive and non-corrosive media 17-4PH -40～400 40～45HRC Medium with slight corrosion but erosion Cr13 -101～400 37～42HRC Medium with slight corrosion but erosion Taili Alloy-268～650 40-45HRC (normal temperature) 38HRC(650C) with erosion and corrosion medium Monel K S-240～482 27～35HRC 30～38HRC Alkali, salt, food, without air Hastelloy B C 371 538 14HRC 23HRC corrosive mineral acid, sulfuric acid, phosphoric acid, wet hydrochloric acid gas, chlorine-free acid solution, ammonium oxidizing medium Alloy No. 20 -45.6～316 -253～427 oxidizing medium and various concentration of sulfuric acid.