Specifications
Surface Treatments
Certifications
- ISO 9001 - 2015 Certified
- PED 2014/68/EC
- NACE MR0175/ISO 15156-2
- NORSOK M-650
- DFAR
- MERKBLATT AD 2000 W2/W7/W10
21CrMoV5-7 Petrochem Reactor Bolts (EN 10269 / 1.7709)
21CrMoV5-7 petrochem reactor bolts are specified into hydrocracker manway bolting, reformer main-flange bolting, isomerisation-reactor manway bolting, and selected ethylene-cracker quench-tower bolting where process-side temperature sits in the 250 to 540 deg C window. The Cr-Mo-V Q+T chemistry handles intermediate-temperature petrochem service where carbon-Mo grades fall short on creep.
Service Envelope
| Reactor type | Typical service temp | 21CrMoV5-7 use |
|---|---|---|
| Hydrocracker reactor manway | 350 to 450 deg C | Primary choice |
| Catalytic reformer reactor | 500 to 540 deg C | Primary choice |
| Isomerisation reactor | 200 to 300 deg C | Acceptable; 42CrMo4 acceptable |
| Ethylene quench tower | 350 to 540 deg C | Primary choice |
| Hydrotreater reactor | 320 to 430 deg C | Primary choice |
Bolting Form Factors Used
- Stud Bolts: main-flange and manway stud bolting (the dominant petrochem reactor fastener)
- Heavy Hex Bolts: inspection-port and access-door bolting
- Tap Studs: selected reactor designs with blind-tap-end bolting
- Heavy hex nuts to ASME B18.2.2 in matched grade
Mechanical Floors for Petrochem Reactor Bolts Service
| Property | Value | Condition |
|---|---|---|
| Tensile (Rm) | 700 to 850 MPa | RT, Q+T |
| 0.2 percent proof stress (Rp0.2) | ≥550 MPa | RT, Q+T |
| Elongation A5 | ≥16 percent | RT, longitudinal |
| Charpy V impact (KV) | ≥63 J | 20 deg C |
| 0.2 percent proof at 500 deg C | ≥450 MPa | elevated-temp |
| Hardness | 210 to 250 HBW | Q+T |
Standards Anchor
21CrMoV5-7 petrochem reactor bolting to EN 10269. Cross-procurement on US-design reactors (UOP, Honeywell, KBR, Shell licensed processes) uses ASTM A193 Grade B16 with dual-certification. Pressure-vessel parallel approval to VdTUV Wb 350 for German-licensed processes.
When to Step Up the Grade
For service above 550 deg C metal temperature, the design steps up to Durehete 1055 (Alloy T41 / Werkstoff 1.7729 / 20CrMoVTiB4-10) with Ti+B microalloying for extended creep envelope. For heavier sections of the same temperature window, sister grade 21CrMoV5-11 (1.8070) provides extended hardenability.
Frequently Asked Questions
Q. Are 21CrMoV5-7 bolts NACE-trim for sour-service petrochem reactors?
No. NACE MR0175 sour-service applications require ASTM A193 Grade B7M (Cr-Mo low-hardness, no V) below 22 HRC. 21CrMoV5-7 falls in the 20 to 26 HRC range and is not NACE-acceptable for direct H2S contact.
Q. Which UOP / Honeywell / KBR processes use 21CrMoV5-7 reactor bolting?
UOP hydrocracking (Unicracking, RCD-Unionfining), KBR ethylene cracking (Score furnace), Shell licensed hydrotreating (S-Max), and Honeywell catalytic reforming (CCR Platforming) commonly call out 21CrMoV5-7 or its ASTM A193 B16 cross-reference for reactor manway and main-flange bolting at intermediate temperatures.
Q. What inspection categories are typical for petrochem reactor bolting?
EN 10204 type 3.2 with Lloyd's, DNV, BV, SGS or TUV witness inspection as standard practice on hydrocracker and reformer reactor bolting. Additional ASNT Level III ultrasonic inspection on the bolting blanks above OD 100 mm.
Q. How does petrochem reactor bolting differ from heat-exchanger bolting?
Reactor bolting typically larger diameter (M64 to M120 vs M30 to M64), longer (>1 m stud lengths common on hydrocracker manways), and held to tighter dimensional and metallurgical tolerances. Both use the same 21CrMoV5-7 chemistry; the form-factor and certification scope differ.
Related Applications
More 21CrMoV5-7 service applications: Steam Turbine Bolts · Gas Turbine Bolts · Power Plant Bolting · Pressure Vessel Bolts · Boiler Bolts · Heat Exchanger Bolts · Fired Heater Bolts. Back to the 21CrMoV5-7 Alloy Hub.
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