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 Welding Wire (Matched Cr-Mo-V Filler)
21CrMoV5-7 welding wire (also called matched-chemistry filler) is the AWS-classified consumable for joining 21CrMoV5-7 (Werkstoff 1.7709) bolting steel base material. Matched-composition Cr-Mo-V low-hydrogen filler for SMAW (AWS A5.5 E9018-B3L), GTAW (AWS A5.28 ER90S-B3L), SAW (AWS A5.23 EB3 wire with appropriate flux), and FCAW (AWS A5.29 E91T1-B3) processes. Required for any welded joint on 21CrMoV5-7 hardware where post-weld heat treatment will re-temper the heat-affected zone to restore creep performance.
Filler Metal Classifications
| Process | AWS classification | EN ISO equivalent | Typical product |
|---|---|---|---|
| SMAW (stick electrode) | AWS A5.5 E9018-B3L | EN ISO 3580-A E CrMo2 B 4 2 H5 | Low-hydrogen basic-coated stick |
| GTAW (TIG) | AWS A5.28 ER90S-B3L | EN ISO 21952-A G CrMo2Si | Solid wire 1.6/2.4/3.2 mm |
| SAW (submerged arc) | AWS A5.23 EB3 wire | EN ISO 24598-A S CrMo2 | Wire 2.5/3.2/4.0 mm + appropriate flux |
| FCAW (flux core) | AWS A5.29 E91T1-B3 | EN ISO 17634-A T CrMo2 B M | Rutile or basic flux-cored wire 1.2/1.6 mm |
Wire Diameter Range
Solid GTAW wire: 1.6, 2.0, 2.4, 3.2 mm — supplied in 5 kg or 15 kg spool, cut-length 36 inch (914 mm) or 1000 mm. SAW wire: 2.5, 3.2, 4.0 mm — supplied in 25 kg coil or drum pack. SMAW stick electrodes: 2.5, 3.2, 4.0, 5.0 mm — supplied in 5 kg vacuum-packed cartons. FCAW wire: 1.2, 1.6 mm — supplied in 15 kg spool with sealed gas-tight package.
Inspection
EN 10204 type 3.1 mill test certificate by default with full chemistry on the deposit, all-weld-metal tensile at room temperature and at 540 deg C, Charpy V impact at 20 deg C on the deposit, diffusible hydrogen content (cap 5 ml per 100 g deposited to EN ISO 3690 / AWS A4.3), and hardness on the weld and HAZ. Type 3.2 with witness on call-out. Manufacturer's certificate to AWS A5.5 (or applicable AWS classification) plus the alloy modification declaration. WPS qualification to ASME Section IX or EN ISO 15614-1 held by the project welding engineer.
Storage and Handling
Low-hydrogen consumables require humidity-controlled storage. SMAW electrodes: re-bake at 350 deg C for 1 hour then transfer to 100-150 deg C holding oven; consume within 8 hours of removal from holding. GTAW + SAW wire: vacuum-packed or nitrogen-purged delivery; transfer to dry-storage cabinet (less than 50 percent relative humidity at 20 deg C) and consume within 30 days of pack opening. Diffusible hydrogen cap of 5 ml per 100 g deposited to ISO 3690 / AWS A4.3.
21CrMoV5-7 Chemistry (Werkstoff 1.7709 Element Ranges)
21CrMoV5-7 (Werkstoff 1.7709) chemistry is fixed within a tight Cr-Mo-V Q+T window to EN 10269. Carbon at 0.17 to 0.25 percent gives the Q+T hardenability backbone without over-hardening for the secondary temper. Chromium at 1.20 to 1.50 percent provides through-thickness hardenability and stabilises the carbide network for creep. Molybdenum at 0.55 to 0.80 percent suppresses temper embrittlement and contributes to the secondary hardening peak. Vanadium at 0.20 to 0.35 percent drives the V4C3 precipitation during the 680 to 740 deg C temper that locks in the creep envelope. The chemistry window is shared with the AFNOR 20CDV5.7 (French) and Polish 21HMF designations.
| Element | Min % | Max % | Role |
|---|---|---|---|
| Carbon (C) | 0.17 | 0.25 | Q+T hardenability |
| Silicon (Si) | — | 0.40 | Deoxidation |
| Manganese (Mn) | 0.40 | 0.80 | Hardenability + solid-solution |
| Phosphorus (P) | — | 0.030 | Tramp limit for toughness |
| Sulphur (S) | — | 0.030 | Tramp limit |
| Chromium (Cr) | 1.20 | 1.50 | Hardenability + creep |
| Molybdenum (Mo) | 0.55 | 0.80 | Secondary hardening |
| Vanadium (V) | 0.20 | 0.35 | V4C3 carbide strengthening |
| Nickel (Ni) | — | 0.60 | Residual |
| Aluminium (Al) | — | 0.030 | Grain refinement |
21CrMoV5-7 Mechanical Properties
21CrMoV5-7 in the quenched-and-tempered condition holds tensile 700 to 850 MPa, 0.2 percent proof stress at least 550 MPa, elongation A5 at least 16 percent, and Charpy V impact at least 63 J at 20 deg C to EN 10269 acceptance. Typical mill datasheet values run 10 to 20 percent above the standard floor. Elevated-temperature 0.2 percent proof stress holds 450 MPa at 500 deg C and 420 MPa at 550 deg C.
| Property | Value | Condition |
|---|---|---|
| Tensile (Rm) | 700 to 850 MPa | RT, Q+T |
| 0.2 percent proof (Rp0.2) | ≥550 MPa | RT, Q+T |
| Elongation A5 | ≥16 percent | RT, longitudinal |
| Charpy V impact (KV) | ≥63 J | 20 deg C, longitudinal |
| 0.2 percent proof at 500 deg C | ≥450 MPa | EN 10269 elevated-temp |
| Hardness (HBW) | 210 to 250 | Q+T condition |
Creep Performance at 500-550 deg C (EN 10269 Annex A)
The defining value-prop of 21CrMoV5-7 is the secondary-hardening creep envelope driven by V4C3 carbide precipitation. The fine V4C3 dispersion formed during the 680 to 740 deg C temper pins dislocation motion during long-time elevated-temperature service. The result is a 100,000-hour stress-rupture envelope to EN 10269 Annex A of approximately 340 MPa at 500 deg C, 290 MPa at 525 deg C, 260 MPa at 540 deg C, and 180 MPa at 550 deg C. Above 550 deg C the V4C3 coarsens faster than the design can tolerate; this is the boundary where the design must step up to Durehete 1055 (Alloy T41 / 1.7729).
Heat Treatment (Q+T Cycle)
The standard cycle for 21CrMoV5-7 is austenitisation at 880 to 940 deg C with hold time of 1 hour per 25 mm section, followed by oil quench. The temper is at 680 to 740 deg C for minimum 2 hours then air cool. The temper temperature is chosen to land on the secondary-hardening peak; below 660 deg C the V4C3 carbide precipitation is under-developed and long-term creep performance suffers; above 750 deg C the carbides over-coarsen and the room-temperature yield drops below the EN 10269 floor of 550 MPa.
Welding Procedure (Matched Cr-Mo-V Filler + PWHT)
21CrMoV5-7 is welded with matched-composition Cr-Mo-V low-hydrogen filler (AWS A5.5 E9018-B3L for SMAW, AWS A5.28 ER90S-B3L for GTAW, AWS A5.23 EB3 for SAW) under preheat 200 to 300 deg C and diffusible-hydrogen cap of 5 ml per 100 g deposited. Post-weld heat treatment at 690 to 720 deg C for 1 hour per 25 mm joint thickness, minimum 2 hours, slow furnace cool to 300 deg C then air cool. The PWHT re-tempers the heat-affected zone and restores creep performance.
Material Selection: 21CrMoV5-7 vs ASTM A193 B16 vs B7 vs Durehete 1055
21CrMoV5-7 sits between ASTM A193 Grade B7 (carbon-Mo only, capped at 450 deg C) and Durehete 1055 (Alloy T41 with Ti+B microalloying, 568 deg C envelope). Direct US cousin: ASTM A193 Grade B16. Dual-certification on call-out.
21CrMoV5-7 Applications by Industry
21CrMoV5-7 covers the bolting envelope from 450 to 550 deg C continuous metal temperature across power generation, refinery and petrochem sectors.
- Steam Turbine Bolts
- Gas Turbine Bolts
- Power Plant Bolting
- Pressure Vessel Bolts
- Boiler Bolts
- Heat Exchanger Bolts
- Fired Heater Bolts
- Petrochem Reactor Bolts
Related 21CrMoV5-7 Forms and Fasteners
21CrMoV5-7 is supplied across the full bolting form-factor range, all to EN 10269 with EN 10204 type 3.1 mill test certificate by default and type 3.2 with third-party witness on call-out.
- Round Bar: raw stock OD 16 to 300 mm
- Bolts (Hub): all bolt form-factors
- Stud Bolts: M12 to M120, lengths 50 to 800 mm
- Hex Bolts + Heavy Hex Bolts
- Tap Studs + Body-Bound Studs
- Weld Studs: drawn-arc stud-welded fasteners
- Anchor Bolts + U-Bolts
- Threaded Rod + Welding Wire
- Nuts + Washers
- Forgings: closed-die and open-die blanks up to 800 kg
Request a Quote
TorqBolt supplies 21CrMoV5-7 (Werkstoff 1.7709) bolting stock and finished fasteners worldwide from Mumbai head office and Rajkot production plant. Type 3.1 EN 10204 mill test certificate by default; type 3.2 with Lloyd's Register, DNV, BV, SGS or TUV witness inspection on call-out. Send your enquiry →
Frequently Asked Questions
Q. Why is matched-composition Cr-Mo-V filler required on 21CrMoV5-7?
Welded joints must restore the creep performance of the parent metal after PWHT. Matched chemistry ensures the weld metal and parent metal develop the same V4C3 secondary-hardening response during the 690-720 deg C PWHT cycle. Mismatched filler (carbon-Mo only, no V) produces a creep-weak weld that fails at the joint over long-term service.
Q. What is the diffusible hydrogen limit for 21CrMoV5-7 welding?
Cap 5 ml per 100 g deposited weld metal to EN ISO 3690 or AWS A4.3 test method. Higher diffusible hydrogen risks HAZ cracking in the Cr-Mo-V chemistry under restraint stress. Low-hydrogen consumables stored to the manufacturer humidity-control requirements.
Q. Can I substitute B3L filler for 21CrMoV5-7?
AWS A5.5 E9018-B3L is the closest matched-chemistry classification. Yes — both share the Cr-Mo-V chemistry window and the low-hydrogen requirement. The B3L designation indicates low-hydrogen control suitable for the 21CrMoV5-7 chemistry.
Q. Do you supply welding wire alongside 21CrMoV5-7 bolting stock?
Yes. Matched-chemistry filler for SMAW + GTAW + SAW + FCAW ships from TorqBolt as part of the 21CrMoV5-7 fastener supply package on call-out. Heat-lot traceability between the bolting bar and the matched filler is documented on the EN 10204 type 3.1 certificate.
Q. What is the AWS A5.5 B3L vs B3 difference?
The "L" suffix indicates "Low Carbon" — carbon capped at 0.05 percent vs 0.10 percent for the standard B3. The L variant gives better impact toughness and lower HAZ hardness. For 21CrMoV5-7 the L variant is preferred for thick sections and for high-cycle service where HAZ toughness matters.
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