The triple‑offset hard‑to‑hard all‑metal butterfly valve is a high‑performance metal‑to‑metal hard‑seated butterfly valve. It adopts a triple‑offset structural design. The seat consists of a metal base overlaid with STL (Stellite) hard‑alloy weld layer, forming an all‑metal sealing structure with outstanding high‑temperature and wear‑resistant properties.
Compared with conventional soft‑seated butterfly valves, this design can withstand higher operating temperatures and more severe industrial working conditions. The triple‑offset geometry enables nearly friction‑free or low‑friction operation between the disc and seat during opening and closing, which greatly reduces wear on the sealing surfaces and extends the service life of the valve.
With Stellite hard‑faced overlay on the sealing face, the seat delivers excellent resistance to wear, erosion, high temperature and galling. It is suitable for high‑temperature, high‑pressure services, steam, flue gas, hot air, oil products and certain corrosive media.
Working Principle of All‑Metal‑to‑Metal Flanged Butterfly Valve:
Friction‑free Opening with Triple‑Offset Design: Driven by a handwheel or gear operator, the valve stem rotates. Thanks to the triple‑offset structure, the butterfly disc lifts completely off the Stellite (STL)‑faced seat at the initial opening angle. No contact or frictional wear occurs throughout the travel, which greatly prolongs the service life of sealing surfaces. When the disc rotates to the 90° fully‑open position, the flow passage is fully unobstructed for smooth medium flow.
Wedge‑Shaped Metal‑to‑Metal Sealing for Closure: As the valve stem rotates in the reverse direction, the disc gradually engages with the conical surface of the seat. Upon completing the closing stroke, the metal‑to‑Stellite hard sealing surfaces form a precise line‑contact wedge seal. Higher medium pressure creates tighter sealing, achieving bi‑directional bubble‑tight shut‑off and completely cutting‑off the pipeline medium.
Manual butterfly valves are widely used in industrial piping systems for fast and reliable flow isolation and regulation. Key parameters including working temperature, medium, pressure rating, valve size and connection standard should be confirmed before ordering for proper valve selection. Customized valve sizes, pressure ratings, connection types, sealing materials and body materials are available for diverse industrial and non-standard applications. (Unit: mm)

| DN | in | Type/Class | Part No | L | D | D1 | D2 | b | Z-φd | Do | H1 | H | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 40 | 1.5 | D343-150LB | D343P150XLX1.5 | 106 | 127 | 98.5 | 73 | 15 | 4-15 | 140 | 76 | 248 | |
| 50 | 2 | D343-150LB | D343P150XLX2 | 108 | 152 | 120.5 | 92 | 16 | 4-19 | 140 | 85 | 254 | |
| 65 | 2.5 | D343-150LB | D343P150XLX2.5 | 112 | 178 | 139.5 | 105 | 18 | 4-19 | 160 | 95 | 278 | |
| 80 | 3 | D343-150LB | D343P150XLX3 | 114 | 190 | 152.5 | 127 | 19 | 4-19 | 160 | 106 | 312 | |
| 100 | 4 | D343-150LB | D343P150XLX4 | 127 | 229 | 190.5 | 157 | 24 | 8-19 | 180 | 114 | 330 | |
| 125 | 5 | D343-150LB | D343P150XLX5 | 140 | 254 | 216 | 186 | 24 | 8-22 | 180 | 130 | 368 | |
| 150 | 6 | D343-150LB | D343P150XLX6 | 140 | 279 | 241.5 | 216 | 26 | 8-22 | 230 | 148 | 404 | |
| 200 | 8 | D343-150LB | D343P150XLX8 | 152 | 343 | 298.5 | 270 | 29 | 8-22 | 230 | 176 | 496 | |
| 250 | 10 | D343-150LB | D343P150XLX10 | 165 | 406 | 362 | 324 | 31 | 12-25 | 280 | 210 | 558 | |
| 300 | 12 | D343-150LB | D343P150XLX12 | 178 | 483 | 432 | 381 | 32 | 12-25 | 310 | 23B | 632 | |
| 350 | 14 | D343-150LB | D343P150XLX14 | 190 | 533 | 476 | 413 | 35 | 12-29 | 310 | 270 | 672 | |
| 400 | 16 | D343-150LB | D343P150XLX16 | 216 | 597 | 540 | 470 | 37 | 16-29 | 310 | 302 | 714 | |
| 450 | 18 | D343-150LB | D343P150XLX18 | 222 | 635 | 578 | 533 | 40 | 16-32 | 380 | 332 | 768 | |
| 500 | 20 | D343-150LB | D343P150XLX20 | 229 | 699 | 635 | 584 | 43 | 20-32 | 380 | 370 | 828 | |
| 600 | 24 | D343-150LB | D343P150XLX24 | 267 | 813 | 749.5 | 692 | 48 | 20-35 | 450 | 432 | 952 | |
| 40 | 1.5 | D343-300LB | D343P300XLX1.5 | 106 | 156 | 114.5 | 73 | 21 | 4-22 | 140 | 76 | 248 | |
| 50 | 2 | D343-300LB | D343P300XLX2 | 108 | 165 | 127 | 92 | 23 | 8-19 | 140 | 85 | 254 | |
| 65 | 2.5 | D343-300LB | D343P300XLX2.5 | 112 | 190 | 149 | 105 | 26 | 8-22 | 180 | 95 | 288 | |
| 80 | 3 | D343-300LB | D343P300XLX3 | 114 | 210 | 168.5 | 127 | 29 | 8-22 | 180 | 106 | 322 | |
| 100 | 4 | D343-300LB | D343P300XLX4 | 127 | 254 | 200 | 157 | 32 | 8-22 | 230 | 122 | 355 | |
| 125 | 5 | D343-300LB | D343P300XLX5 | 140 | 279 | 235 | 186 | 35 | 8-22 | 230 | 140 | 392 | |
| 150 | 6 | D343-300LB | D343P300XLX6 | 140 | 318 | 270 | 216 | 37 | 12-22 | 280 | 156 | 428 | |
| 200 | 8 | D343-300LB | D343P300XLX8 | 152 | 381 | 330 | 270 | 42 | 12-25 | 280 | 186 | 520 | |
| 250 | 10 | D343-300LB | D343P300XLX10 | 165 | 445 | 387.5 | 324 | 48 | 16-29 | 310 | 220 | 574 | |
| 300 | 12 | D343-300LB | D343P300XLX12 | 178 | 521 | 451 | 381 | 51 | 16-32 | 380 | 250 | 668 | |
| 350 | 14 | D343-300LB | D343P300XLX14 | 190 | 584 | 514.5 | 413 | 54 | 20-32 | 380 | 288 | 708 | |
| 400 | 16 | D343-300LB | D343P300XLX16 | 216 | 648 | 571.5 | 470 | 58 | 20-35 | 380 | 322 | 750 | |
| 450 | 18 | D343-300LB | D343P300XLX18 | 222 | 711 | 628.5 | 533 | 61 | 24-35 | 450 | 348 | 802 | |
| 500 | 20 | D343-300LB | D343P300XLX20 | 229 | 775 | 686 | 584 | 64 | 24-35 | 450 | 378 | 862 | |
| 600 | 24 | D343-300LB | D343P300XLX24 | 267 | 914 | 813 | 692 | 70 | 24-41 | 560 | 434 | 1006 |
The all‑metal‑to‑metal butterfly valve can be supplied with carbon steel, stainless steel, alloy steel and other valve‑body materials to suit different working conditions. Designed with triple‑offset geometry and an all‑metal hard‑sealed structure, its seat is hard‑faced with Stellite (STL) overlay. It features low friction and low wear, making it suitable for high‑temperature, high‑pressure and severe‑service applications. The valve can be fitted with manual, gear, electric or pneumatic actuators. It is widely used in petroleum, chemical, power generation, metallurgy, iron‑and‑steel, heating and energy industries.