The material for high temperature industrial valve

Working temperature is a key factor should be taken into consideration for valve design, manufacture and inspection. Generally, the operating temperature t > 425℃ valve is referred to as a high-temperature valve, but the number is difficult to distinguish the temperature range of high temp valve. High temp valve including high temp gate valve, high temperature globe valve, high temperature check valve, high temperature ball valve, high temperature butterfly valve, high temperature needle valve, high temperature throttle valve, high temperature pressure reducing valve. Among them, the most commonly used are gate valve, globe valve, check valve, ball valve and butterfly valve. High temp valves are widely used in petrochemical, chemical fertilizer, electric power and metallurgy industries. According to ASME B16.34, the material of the valve body and interior part are different in each temperature range. In order to ensure the valve in accordance with its corresponding high temp working conditions, it is absolutely necessary to scientifically and reasonably design and distinguish the high temp level of valve.

Some high temp valve manufacturers divide high temperature valves into five grades according to temp rating based on its production experience. That is, the valve operating temperature t>425~550℃ is grade PI, t>550~650℃ is grade PII, t>650~730℃ is grade PIII, t>730~816℃ is grade PIV, and t>816℃ is grade PV. Among them, PI~PIV valve mainly depends on the selection of appropriate materials to ensure its performance, PV valve in addition to material selection is more important to use special design such as lining insulation lining or cooling measures. High-temperature valve design should pay attention to the use of temperature shall not exceed the maximum allowable use temperature of the material. According to ASMEB31.3, the maximum temperature of common high-temperature valve materials is shown in the following table. Special note is that in the actual design of the valve also consider the corrosive medium and stress levels and other factors, the allowable temperature of the valve material is actually lower than the table.

 

Pressure-temperature rating for commonly used stainless steel:

Workworn temp  Material Pound class working pressure, pounds per square inch
150 300 400 600 900 1500 2500 4500
800℉

(427℃)

CF8, 304, 304H 80 405 540 805 1210 2015 3360 6050
CF8M, 316, 316H 80 420 565 845 1265 2110 3520 6335
321, 321H 80 450 600 900 1355 2255 3760 6770
CK-20, 310, 310H 80 435 580 875 1310 2185 3640 6550
1000℉

(538℃)

CF8, 304, 304H 20 320 430 640 965 1605 2625 4815
CF8M, 316, 316H 20 350 465 700 1050 1750 2915 5245
321, 321H 20 355 475 715 1070 1785 2970 5350
CK-20, 310, 310H 20 345 460 685 1030 1720 2865 5155
1200℉

(650℃)

CF8, 304, 304H 20(1) 155 205 310 465 770 1285 2315
CF8M,316,316H 20(1) 185 245 370 555 925 1545 2775
321, 321H 20(1) 185 245 365 555 925 1545 2775
CK-20, 310, 310H 20(1) 135 185 275 410 685 1145 2055
1350℉

(732℃)

CF8, 304, 304H 20(1) 60 80 125 185 310 515 925
CF8M, 316, 316H 20(1) 95 130 190 290 480 800 1440
321, 321H 20(1) 85 115 170 255 430 715 1285
CK-20, 310, 310H 20(1) 60 80 115 175 290 485 875
1500℉

(816℃)

CF8, 304, 304H 10(1) 25 35 55 80 135 230 410
CF8M, 316, 316H 20(1) 40 55 85 125 205 345 620
321, 321H 20(1) 40 50 75 115 190 315 565
CK-20, 310, 310H 10(1) 25 35 50 75 130 215 385

 

Pressure – temperature rating of Cr – Mo high-temperature steel

Working temp Grades Pound class working pressure, pounds per square inch
150 300 400 600 900 1500 2500 4500
800℉

(427℃)

WC4, WC5, F2 80 510 675 1015 1525 2540 4230 7610
WC6, F11C1.2, F12C1.2, 80 510 675 1015 1525 2540 4230 7610
WC9, F22C1.3 80 510 675 1015 1525 2540 4230 7610
C5, F5 80 510 675 1015 1525 2540 4230 7610
1000℉

(538℃)

WC4, WC5, F2 20 200 270 405 605 1010 1685 3035
WC6, F11C1.2, F12C1.2, 20 215 290 430 650 1080 1800 3240
WC9, F22C1.3 20 260 345 520 780 1305 2170 3910
C5, F5 20 200 265 400 595 995 1655 2985

 

In short, high temp valve with the operating temperature higher than 425℃, the main material of which is alloy steel or stainless steel or Cr-Ni heat resistant alloy. Actually, in practice application, the material WCB(or A105) is also widely used in the main body of the valve, such as high-temperature ball valve, check valve and butterfly valve. When the working temperature of the ball valve with PTFE and rubber as sealing ring is higher than 150 ~ 180℃, it is not recommended to use the counterpoint polystyrene seat (working temperature t≤320℃) or metal seat, that is proper “high-temperature ball valve”.

0 replies

Leave a Reply

Want to join the discussion?
Feel free to contribute!

Leave a Reply

Your email address will not be published. Required fields are marked *