¿Qué son WCB, LCB, LCC, WC6 y WC??
W significa fundición y C acero al carbono; A, B y C indican el valor de resistencia del grado de acero de menor a mayor. WCA, WCB, WCC representan acero al carbono. ABC representa el nivel de fuerza y comúnmente se usa WCB. El material de tubería correspondiente a WCB es A106B, y el material de forja correspondiente es A105. WC6 es una fundición de acero aleado. El material de la tubería correspondiente es A355 P11 y la forja correspondiente es A182 F11. Además, WC9 es una aleación de acero resistente a altas temperaturas. WC es la fundición soldable. LCB o LCC (ASTM A352) es acero al carbono de baja temperatura.
Piezas fundidas y forjadas de acero al carbono comunes utilizadas para válvulas
W significa fundición y C acero al carbono; A, B y C indican el valor de resistencia del grado de acero de menor a mayor. WCA, WCB, WCC representan acero al carbono. ABC representa el nivel de fuerza y comúnmente se usa WCB. El material de tubería correspondiente a WCB es A106B, y el material de forja correspondiente es A105. WC6 es una fundición de acero aleado. El material de la tubería correspondiente es A355 P11 y la forja correspondiente es A182 F11. Además, WC9 es una aleación de acero resistente a altas temperaturas. WC es la fundición soldable. LCB o LCC (ASTM A352) es acero al carbono de baja temperatura.
Piezas fundidas y forjadas de acero al carbono comunes utilizadas para válvulas
| Countries | Standards | Grades | ||
| USA | ASTM A216/A216M | WCA | WCB | WCC |
| UNS J02502 | UNS J03002 | UNS J02503 | ||
| USA | ASTM A105/A105M | A105 | ||
Grades and applicable temperatures of low-temperature steel casting
| Types | C | C | C-Mn | C-Mo | 2.5Ni | Ni-Cr-Mo | 3.5Ni | 4.5Ni | 9Ni | Cr-Ni-Mo |
| Grades | LCA | LCB | LCC | LC1 | LC2 | LC2-1 | LC3 | LC4 | LC9 | CA6NM |
| UNS numbers | J02504 | J03303 | J02505 | J12522 | J22500 | J42215 | J31550 | J41500 | J31300 | J91540 |
| Applicable temperatures ℃ | -32 | -46 | -46 | -59 | -73 | -73 | -101 | -115 | -196 | -73 |
Commonly used ASTM materials for valves and castings (ASME B16.5)
| ASTM castings | ASTM forgings | Applicable temperatures ℃ | Applicable media |
| Carbon steel | |||
| A216 WCB | A105 | -29 to 427 | Water, steam, air, petroleum products, etc. |
| Low-temperature carbon steel | |||
| A352 LCB | A350 LF2 | -46 to 343 | Low-temperature media |
| A352 LCC | A350 LF2 | -46 to 343 | Low-temperature media |
| High-temperature alloy steel | |||
| A217 WC1 | A182 F1 | -29 to 454 | High-temperature and high-pressure media |
| A217 WC6 | A182 F11 | -29 to 552 | High-temperature and high-pressure media |
| A217 WC9 | A182 F22 | -29 to 593 | High-temperature and high-pressure media |
| A217 C5 | A182 F5 | -29 to 650 | Corrosive high-temperature media |
| A217 C12 | A182 F9 | Cr9Mo1 | -29 to 593 | Media containing high sulfur oxidizing |
| Martensitic stainless steel | ||||
| A217 CA15 | A182 F6a | 1Cr13 | -29 to 371 | Lower strength than 304 at a temperature of 450℃ |
| Austenitic stainless steel (C being less than and equal to 0.08) | ||||
| A351 CF8 | A182 F304 | 0Cr18Ni9 | -196 to 537 | Corrosive media |
| A351 CF3 | A182 F304L | -196 to 425 | Corrosive media | |
| A351 CF8M | A182 F316 | 0Cr18Ni12Mo2Ti | -196 to 537 | Corrosive media |
| A351 CF3M | A182 F316L | -196 to 425 | Corrosive media | |
| Ultra-low carbon austenitic stainless steel (C being less than and equal to 0.03) | ||||
| A351 CF3 | A182 F304L | 00Cr18Ni10 | -196 to 427 | Corrosive media |
| A351 CF3M | A182 F316L | 00Cr18Ni14Mo2 | -196 to 454 | Corrosive media |
| Special alloys | ||||
| A351 CN7M | B462 Gr. NO8020 (ALLOY 20) |
-29 to 149 | Oxidizing media and sulfuric acid with various concentrations | |
| A494 M-30C (Monel) |
B564 Gr. NO4400 | -29 to 482 | Hydrofluoric acid and seawater | |
| Hastelloy H.B H.C | Strong corrosive media such as dilute sulfuric acid | |||
Please note that the material of the forged valve body is dense, not easy to be defective; the structure size is not limited by the mold, and the pressure bearing performance is reliable. It is mostly used for manufacturing valves with high pressure, oxygen, small diameters or other small batches. Forgings are selected under high temperature, high pressure, low temperature or special media; castings are generally only suitable for medium and low pressure, and are mostly used in the mass production of standardized formed valves. The difference between A351 CF3M and A182 F316L: The material corresponding to the two standards is 316 stainless steel. CF3M stands for casting and is often used as a valve material. The corresponding forged steel is A182 F316L. ASTM A216 WCB is a casting, and its forging is A105; the casting of SS304 is A351 CF8, and its forging is A182 F304.
The selection of valve materials
There are many materials for manufacturing valve parts, including various grades of ferrous and non-ferrous metals and their alloys, and various non-metallic materials. Materials for making valve parts are selected based on the following factors:
- The pressure, temperature and characteristics of the working medium
- The force bearing by the part and its role in the valve's structure
- Good manufacturability
- Combining low costs with the above conditions
Materials for valve bodies, bonnets and discs
- Gray cast iron: it is suitable for water, steam, air, gas, oil and other media with nominal pressure PN being less than and equal to 1.0MPa and temperatures between -10℃ and 200℃.
- Malleable cast iron: it is suitable for water, steam, air and oil with nominal pressure PN being less than and equal to 2.5MPa and temperatures of -30 to 300℃.
- Ductile iron: it is suitable for media such as water, steam, air and oil with PN being less than and equal to 4.0MPa and temperatures of -30 to 350℃.
- Carbon steel (WCA, WCB and WCC): it is suitable for nominal pressure PN being less than and equal to 32.0MPa, medium and high pressure valves with working temperatures between -29 to +425℃.
- Low-temperature carbon steel (LCB): it is applied to ethylene, propylene, liquid natural gas, liquid nitrogen and other media with nominal pressure PN being less than and equal to 6.4Mpa, temperatures greater than and equal to -196℃.
- Alloy steel (WC6, WC9): it is used for high-temperature and high-pressure valves with non-corrosive media with working temperatures between -29 to 595℃; WC5 and WC9 are suitable for high-temperature and high-pressure valves containing corrosive media with working temperatures between -29 to 650℃.
- Austenitic stainless steel: it is suitable for valves with corrosive media with operating temperatures between -196 to +600℃.
- Monel alloys: it is mainly suitable for valves with hydrogen fluoride.
- Cast copper alloys: It is mainly suitable for valves used in oxygen pipelines whose working temperatures are between -29 and 595℃.
Table 1-1 Common materials for valve housings
| Materials for valve housings | Standards | Applicable temperatures/℃ | Applicable pressure/MPa | Applicable media |
| Gray cast iron | -15 to 200℃ | Less than and equal to 1.6 | Water and gas | |
| Black heart malleable cast iron | -15 to 300 | Less than and equal to 2.5 | Water, seawater, gas and ammonia | |
| Ductile iron | -30 to 350 | Less than and equal to 4.0 | Water, sea water, gas, air and steam | |
| Carbon Steel (WCA, WCB and WCC) | ASTM A216 | -29 to 425 | Less than and equal to 32.0 | ASTM A216 -29 to 425 water, oil and gas |
| Low-temperature carbon steel (LCB and LCC) |
ASTM A352 | -46 to 345 | Less than and equal to 32.0 | Low temperatures |
| Alloy steel (WC6 and WC9) (C5 and C12) |
ASTM A217 | -29 to 595 -29 to 650 |
High pressure | Non-corrosive media and corrosive media |
| Austenitic stainless steel | ASTM A351 | -196 to 600 | Corrosive media | |
| Monel | ASTM A494 | 400 | Media containing hydrofluoric acid | |
| Hastelloy | ASTM A494 | 649 | Dilute sulfuric acid and other strong corrosive media | |
| Titanium alloys | Various strong corrosive media | |||
| Cast copper alloys | -273 to 200 | Oxygen and seawater | ||
| Plastic and ceramic | to 60 | Less than and equal to 1.6 | Corrosive media |
| Grades | Materials | Standards | Applicable conditions | Temperature ranges |
| WCB | Carbon steel | ASTM A216 | Non-corrosive conditions, including water, oil and gas | -29℃ to +425℃ |
| LCB | Low-temperature carbon steel | ASTM A352 | low temperatures | -46℃ to +345℃ |
| LC3 | 3.5% nickel steel | ASTM A352 | low temperatures | -101℃ to +340℃ |
| WC6 | chromium and 0.5% molybdenum steel | ASTM A217 | Non-corrosive conditions, including water, oil and gas. | -30℃ to +593℃ |
| WC9 | 2.25 chromium | |||
| C5 | 5% chromium and 0.5% molybdenum | ASTM A217 | Mildly corrosive, corroded and non-corrosive applications | -30℃ to +649℃ |
| C12 | 9% chromium and 1% molybdenum | |||
| CA15(4) | 12% chromium steel | ASTM A217 | Corrosive conditions | +704℃ |
| CA6NM(4) | 12% chromium steel | ASTM A487 | Corrosive conditions | -30℃ to +482℃ |
| CF8M | Stainless steel 316 | ASTM A351 | Corrosive, ultra-low temperature or high-temperature non-corrosive applications | The specified carbon content should be 0.04% and above for temperatures between -268°C to +649°C. |
| CF8C | Stainless steel 347 | ASTM A351 | High-temperature and corrosive applications | The specified carbon content should be 0.04% and above at temperatures between 268°C to +649°C. |
| CF8 | Stainless Steel 304 | ASTM A351 | Corrosive or ultra-low temperature or high-temperature non-corrosive applications | The specified carbon content should be 0.04% and above at temperatures between 268°C to +649°C. |
| CF3 | Stainless Steel 304L | ASTM A351 | Corrosive or non-corrosive applications | +425℃ |
| CF3M | Stainless Steel 316L | ASTM A351 | Corrosive or non-corrosive applications | +454℃ |
| CN7M | Alloy steel | ASTM A351 | Having good resistance to hot sulfuric acid corrosion +425℃ | +425℃ |
| M35-1 | Monel | ASTM A494 | Having good resistance to all common organic acids, salt water corrosion and good corrosion resistance to most alkaline solutions | +400℃ |
| N7M | Hastelloy B | ASTM A494 | It is especially suitable for hydrofluoric acid with various concentrations and temperatures, which has good resistance to sulfuric acid and phosphoric acid corrosion. | +649℃ |
| CW6M | Hastelloy C | ASTM A494 | It has good corrosion resistance in strongly oxidizing environments, good properties at high temperatures, good corrosion resistance to formic acid (formic acid), phosphoric acid, sulfurous acid and sulfuric acid. | +649℃ |
| CY40 | Inconel | ASTM A494 | It has good performance in high temperatures and good corrosion resistance for highly corrosive fluid media. |
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