弹簧微启式螺纹安全阀说明：a21f-弹簧微启式螺纹安全阀适用于工作温度≤200℃的空气、氨、石油气……等介质的设备或管路上。a21w-p、r不锈钢安全阀适用于温度≤200℃有腐蚀性的气体或液体的设备或管路上，作为超压保护装置。ka21y型适用于温度≤100℃的液化石油气等。
弹簧微启式螺纹安全阀主要零部件材料
| no. | 零件名称 | a21h-c/a21f材料 | a21w-p/a21f-p材料 | a21y-r材料 |
| 1 | 管接头 | 20 | 1cr18ni9ti | 1cr18ni12mo2ti |
| 2 | 管接头螺母 | 35 | 2cr13 | 1cr18ni9ti |
| 3 | 阀座 | 35 | 1cr18ni9ti | 1cr18ni12mo2ti |
| 4 | 阀体 | 2cr13 | 1cr18ni9ti | 1cr18ni12mo2ti |
| 5 | 阀瓣 | 2cr13/2cr13+ptfe | 1cr18ni9ti/1cr18ni9ti+ptfe | 1cr18ni12mo2ti |
| 6 | 弹簧座 | 2cr13 | 1cr18ni9ti | 1cr18ni12mo2ti |
| 7 | 弹簧 | 50crva | 50crva包覆氟塑料 | 50crva包覆氟塑料 |
| 8 | 锁紧螺母 | q235-a | zg230-450 | 1cr18ni9ti |
| 9 | 弹簧导向垫 | 2cr13 | 1cr18ni9ti | 1cr18ni12mo2ti |
| 10 | 调节螺母 | q235-a | 2cr13 | 1cr18ni12mo2ti |
| 密封面材料 | "y"型堆焊co基硬质合金,"h"型堆焊d507,"w"型为阀门本体 | |||
| 型号 | 公称通径 | do | d | do | m | d1 | d1 | l | l1 | ≈h |
| ka21-16c a21h-16c a21h-40 a21w-16p a21w-40p ka21-16p |
15 | 12 | 15 | 20 | m27×1.5 | g1/2" | 30 | 35 | 76 | 66 |
| 20 | 16 | 20 | 25 | m33×1.5 | g3/4" | 35 | 40 | 87 | 68 | |
| 25 | 18 | 25 | 31 | m39×1.5 | g1" | 40 | 50 | 100 | 105 | |
| a21y-64 a21y-64p a21y-100 a21y-100p |
15 | 10 | 15 | 25 | m39×1.5 | g1" | 44 | 50 | 100 | 66 |
| 20 | 10 | 20 | 31 | m39×1.5 | g1" | 44 | 50 | 100 | 68 | |
| 25 | 12 | 25 | 31 | m39×1.5 | g1" | 44 | 50 | 100 | 105 | |
| a21w-160/160p | 15 | 8 | 20 | / | m24×2 | g1" | 44 | 50 | 100 | 261 |
| 20 | 8 | 25 | / | m33×2 | g1" | 44 | 50 | 100 | 261 | |
| 25 | 8 | 28 | / | m36×2 | g1" | 44 | 50 | 100 | 285 |
