Titanium Grade 12 Fitting, ASTM B363 — R53400 (Ti-0.3Mo-0.8Ni) Fittings from Baoji

Published by Engineering Team, Shaanxi Qianyi Tuoda Technology Co., Ltd on 2026-11-04

Titanium Grade 12 fittings · ASTM B363 · UNS R53400

Grade 12 (UNS R53400, Ti-0.3Mo-0.8Ni) fittings to ASTM B363 give corrosion resistance close to Grade 7 at a fraction of the palladium cost. SXQYTD stocks Grade 12 elbows, tees, reducers, caps and stub ends, with mill test certificate and PMI. Below is the procurement detail that decides type, size and schedule before you issue a PO.

Material	Grade 12 (UNS R53400, Ti-0.3Mo-0.8Ni)	Principle	Mo/Ni boosts strength & acid resistance
Type & stock	Elbow, tee, reducer, cap, stub end	Industry	Chemical, chlor-alkali, desalination, acid
Standard	ASTM B363 / ASME SB-363	Lead time	1–3 days stock; 1–2 weeks custom

1. What a Grade 12 fitting is — by grade and by type

By grade, Grade 12 is unalloyed titanium with small 0.3 % molybdenum and 0.8 % nickel (Ti-0.3Mo-0.8Ni, UNS R53400). That Mo/Ni shift raises the corrosion potential so the passive film survives reducing acids that attack Grade 2, and it adds strength — roughly a grade above Gr2. By type, ASTM B363 covers seamless and welded fittings: elbow (90° / 45°), tee, reducer (concentric / eccentric), cap, and stub end (lap-joint). They are either seamless from extruded pipe or fabricated from tube and welded.

2. Why Grade 12 — grade vs. medium vs. corrosion

Grade 12 sits between Gr2 and Gr7 on cost and performance:

Medium	Recommended grade	Why
Dilute HCl, H₂SO₄ (reducing)	Gr12	Resists where Gr2 fails; cheaper than Gr7.
Wet chlorine, hypochlorite	Gr2 / Gr12	Oxidizing; both acceptable.
Seawater, brine	Gr2 adequate; Gr12 adds margin	Gr12 useful in hot crevices.
vs Grade 7	Gr12	~equal corrosion, no Pd, 30–40 % cheaper.

Two things that sink a titanium fitting if ignored: (1) titanium must never be welded or bolted directly to steel — use isolating gaskets and lined flanges, or galvanic corrosion eats the fitting in an electrolyte; and (2) titanium welding needs argon backing on both sides, so a weld that turns blue or grey is oxygen-contaminated and must be cut out and re-done. We back-purge every seam and colour-check it.

3. Technical standards we build to

• Fitting spec: ASTM B363 / ASME SB-363, seamless or welded, MTC EN 10204 3.1.
• Chemistry (R53400): Mo 0.20–0.40 %, Ni 0.60–0.90 %, Fe ≤ 0.30 %, O ≤ 0.25 %.
• Mechanical (annealed): tensile ≥ 483 MPa, yield ≥ 345 MPa, elongation ≥ 18 %.
• Base material: made from B338/B337 tube or forged stock; PMI on the heat.
• Inspection: PT on welds, dimensional and bevel check, PMI report.

4. Manufacturing flow — from stock to your fitting

1) Gr12 tube / billet release with MTC & PMI → 2) Forming (press-bend elbow, hot-form reducer) or cutting → 3) Fabrication welding if assembled (GTAW, argon back-purge) → 4) Stress-relief anneal → 5) Pickling / passivation → 6) End bevel and dimensional check → 7) PT on seams → 8) PMI → 9) Marking (grade, size, heat) → 10) Export packing. Seamless fittings come straight from extruded pipe; fabricated ones are tube + weld.

5. Key performance

Item	Control value	Note
Tensile strength	≥ 483 MPa	vs Gr2 345 MPa.
Yield strength	≥ 345 MPa	Higher than Gr2.
Weld colour	Silver – light straw	Blue/grey rejected, re-welded.
Surface	Pickled & passivated, PT pass	No α-case.
Density	4.51 g/cm³	Light line, easy support.

6. Application industries

Industry	Medium	Why Grade 12
Chemical acid lines	HCl, H₂SO₄	Reducing acid resistance.
Chlor-alkali	Bleach, wet Cl₂	Strong + oxidizing duty.
Desalination	Seawater, brine	Crevice margin at temperature.
Pharma / fine chem	Organic acids	Clean, metal-ion-free.

7. Selection guide

By medium: reducing acid → Gr12 (or Gr7 if spec-mandated); oxidizing / chloride → Gr2; high strength → Gr5. By type: elbow changes direction, tee adds a branch, reducer changes pipe size, stub end makes a lap-joint connection, cap closes a line. Send medium, size (1/2–24 in), schedule/wall, type and quantity; we confirm grade and availability in one reply.

8. Customizable items & accessories

• Type and size (1/2–24 in), wall / schedule, seamless or welded.
• End bevel (B16.5) or plain end; lap-joint stub ends.
• Surface: pickled, bright-annealed; isolating gaskets available.
• PMI report, heat-number marking, spare pieces.
• Third-party inspection (SGS / TUV), extended traceability.

9. Lead time, test reports & warranty

Item	Commitment
Lead time	1–3 days from stock; 1–2 weeks custom.
Test reports	MTC 3.1, PT, PMI, dimensional & bevel.
Warranty	12 months against material and workmanship defects from shipment.

10. FAQ

Grade 12 or Grade 7 — which should I specify?

In most reducing-acid media they perform in the same corrosion class, but Grade 12 carries no palladium, so it is typically 30–40 % cheaper. Choose Grade 12 unless your spec or client mandate calls out Grade 7 (R52400) by name. We can supply either.

Is ASTM B363 the right standard for Titanium Fittings?

Yes. B363 is the titanium and titanium-alloy fitting specification (elbow, tee, reducer, cap, stub end). Note the flange dimensions follow ASME B16.5, but the material and quality are governed by B363 — don't confuse the two.

Can Grade 12 replace Grade 2?

Yes, wherever you need resistance to reducing acid or extra strength — Gr12's weld and corrosion behaviour are compatible with Gr2 service. If the line is purely oxidizing (seawater, wet chlorine) and cost is tight, Gr2 is the cheaper fit. Send the medium and we advise.