Question 1

What is ASTM A403 WP446?

Accepted Answer

ASTM A403 WP446 is a high-chromium ferritic stainless steel (UNS S44600 / AISI 446, EN 1.4749 approx.) used for butt-weld pipe fittings in severe high-temperature service with excellent oxidation and sulfidation resistance.

Question 2

Which standards do your WP446 butt-weld fittings meet?

Accepted Answer

Dimensional and manufacturing scope aligns with ASME B16.9, ASME B16.28, MSS SP-43, EN 10253-2 (ferritic steels), JIS B2312, and the material framework of ASTM A403/A403M for wrought fittings.

Question 3

What sizes and schedules are available?

Accepted Answer

NPS 1/2″–48″ (DN 15–1200) in seamless and welded construction, covering schedules SCH 5S to SCH XXS; custom wall thicknesses available on request.

Question 4

Typical chemical composition of WP446?

Accepted Answer

C ≤ 0.20, Mn ≤ 1.50, P ≤ 0.040, S ≤ 0.030, Si ≤ 1.50, Cr 23.0–27.0 (high), Ni ≤ 0.25. Minor additions (e.g., Mo, N, Ti, Nb) may be used depending on specification.

Question 5

Typical mechanical properties of WP446 fittings?

Accepted Answer

Tensile ≥ 415 MPa, Yield ≥ 205 MPa, Elongation ≥ 20%, Hardness ≤ 200 HB (≈ 92 HRB). Values are indicative and vary by form and heat treatment.

Question 6

Why choose WP446 for high-temperature service?

Accepted Answer

With ~23–27% chromium, WP446 forms a stable oxide layer offering excellent scaling resistance up to about 1100 °C and superior sulfidation resistance, with good resistance to chloride stress corrosion cracking compared to many austenitic grades.

Question 7

What product types do you supply in WP446?

Accepted Answer

Elbows (LR/SR/180°), tees (equal/reducing/barred/lateral), reducers (concentric/eccentric), caps, stub ends (long/short), crosses, laterals, and custom fabricated pieces for thermal processing lines.

Question 8

What documentation is provided?

Accepted Answer

EN 10204 3.1 MTC with full heat traceability. On request: QAP/ITP, heat-treatment charts, NDE (UT/RT/MT/PT), PMI, hardness/impact/tensile results, dimensional reports; TPI by BV, TÜV, LR, SGS, DNV.

Question 9

Are PED, CE, and IBR supported?

Accepted Answer

Yes—PED/CE and IBR support are available based on project requirements. Share the applicable design code and jurisdiction with your RFQ.

Question 10

How can I request a quote quickly?

Accepted Answer

For the fastest response, WhatsApp +91-9975266499 with your BOQ/drawings and specifications. You can also email info@diptimetal.com and diptimetal@gmail.com.

Question 11

Typical applications for WP446 fittings?

Accepted Answer

Furnace components, burner nozzles, petrochemical heaters, waste heat boilers, kiln linings, hot gas ducting, sulfur recovery units, and other high-temperature oxidizing or sulfur-rich atmospheres.

Question 12

Finishing/condition options?

Accepted Answer

Usually supplied annealed for ductility and toughness; pickled/cleaned surfaces available as required. Welding procedures for ferritic 446 are applied to minimize embrittlement and thermal fatigue.

Question 13

Export & delivery capabilities?

Accepted Answer

Global exports with sea/air/express options and support for EXW, FCA, FOB, CFR, and CIF. We frequently support urgent maintenance shutdowns for furnace/heater applications.

Question 14

Custom fittings to drawings?

Accepted Answer

Yes—custom bends, large-radius elbows, special branches/angles, transitions, and thick-wall components manufactured per client drawings with full QA/QC and traceability.

Question 15

How is quality and traceability ensured?

Accepted Answer

Strict incoming material control, qualified welding/HT procedures, calibrated inspection, NDE per ITP, and line-wise bagging/tagging with heat numbers; complete documentation accompanies each dispatch.

Property	Value
Yield Strength (Rp0.2)	≥ 205 MPa
Tensile Strength (Rm)	≥ 415 MPa
Elongation (A)	≥ 20 %
Hardness	≤ 200 HB (≈ 92 HRB)
Oxidation Resistance	Excellent up to ~1100 °C (service-dependent)
Sulfidation Resistance	Superior due to high Cr
Chloride SCC	Very good vs austenitic grades

System	Designation	Note
UNS	S44600	AISI 446
EN/DIN	1.4749 (X18CrN28)	Heat-resisting SS, approx.
JIS	SUS 446	Japan
BS	446S60	UK
GOST	15Х28 (15Kh28)	Approx.

Topic	Primary Reference	Also Refer	What It Covers	Notes
Dimensions	ASME B16.9 / B16.28	MSS SP-43 (light-wall SS)	Elbows, tees, reducers, caps, stub ends geometry	Used for dimensional conformity
Ferritic Material Basis	EN 10253-2	EN 10095; ASTM A240/A268 (forms)	Wrought ferritic fittings & material rules (EU)	Common for ferritic SS projects
Inspection & MTC	EN 10204 3.1 / 3.2	TPI: BV, TÜV, LR, SGS, DNV	Certification, traceability, test reports	3.2 via authorized inspector
Welding	WPS/PQR/WPQ	ASME IX / EN ISO 15614	Qualification for ferritic stainless welding	Heat input control recommended
Quality Docs	QAP/ITP	Project-specific specs	PMI, NDE, dimensional, HT charts	Delivered with shipment

Type	Construction	Sizes	Schedules / WT	Ends	Typical Service
Elbows (LR/SR 45°, 90°, 180°; reducing)	Seamless / Welded	NPS 1/2″–48″	SCH 5S–XXS	BW bevel 37.5°±2.5°	Hot gas ducting, SRUs, heaters
Tees (equal, reducing, barred, laterals)	Seamless / Welded / Fabricated	NPS 1/2″–48″	SCH 5S–XXS	BW bevel	Furnace manifolds, kiln branches
Reducers (concentric / eccentric)	Seamless / Welded	NPS 1/2″–48″	SCH 5S–XXS	BW bevel	Heater coils, exhaust stacks
Caps	Seamless / Welded	NPS 1/2″–48″	Per run pipe	BW bevel / plain	Reactor ends, burner protection
Stub Ends (short/long)	Welded / Machined	NPS 1/2″–48″	SCH 5S–XXS	BW bevel	Lap-joint with alloy rings
Crosses & Laterals	Seamless / Fabricated	NPS 1/2″–48″	Per spec	BW bevel	Complex furnace networks

Category	Includes	Notes
Certificates & Tests	EN 10204 3.1/3.2, PMI, hardness, hydro/pneumatic (as reqd.), NDE (UT/RT/MT/PT)	TPI: BV, TÜV, LR, SGS, DNV as requested
Dimensional & Marking	ASME B16.9/B16.28 dimensions, stamping/etching with grade, heat, size, PO	Barcoding & color coding on request
Packing & Logistics	Seaworthy crates, line-wise bagging & tagging, export documentation	EXW/FCA/FOB/CFR/CIF worldwide

ASTM A403 WP446 Ferritic Stainless Steel Butt-Weld Fittings

🏭 Company Introduction

Standards Note (Important)

📘 Grade & Equivalents — WP446 (UNS S44600 / AISI 446)

Chemical Composition (typical, %)

Mechanical & Service (indicative)

International Equivalents (nearest)

Supply Condition

📚 Key Standards Matrix — WP446 Butt-Weld Fittings

🔧 WP446 Butt-Weld Fittings — Range & Specifications

🌍 Global Supply Chain & Export Destinations

✉️ Request a Quote

📍 Contact

Element	Range
C	≤ 0.20
Mn	≤ 1.50
Si	≤ 1.50
P	≤ 0.040
S	≤ 0.030
Cr	23.0 – 27.0
Ni	≤ 0.25
Others	Mo/N/Ti/Nb when specified