AWS Class E630-16 Welding Electrodes

AWS A5.4 E630-16 Welding Electrode Supplier in Mumbai, India

Nicorex Alloys is an ISO-certified supplier of E630-16 welding electrodes based in Mumbai, India. The weld deposit contains approximately 16.5% Cr, 4.7% Ni, 3.5% Cu, and 0.15% Nb+Ta, designated UNS W37410.

The E630-16 is a rutile-coated stick (SMAW) welding electrode approved under AWS A5.4 and ASME SFA 5.4 for welding ASTM A564 Type 630 (UNS S17400 / 17-4PH) and other similar precipitation-hardening martensitic stainless steels. Unlike other stainless steel electrodes in AWS A5.4, it produces weld metal that can be further strengthened by heat treatment. This is because the weld deposit contains copper and niobium, which form hardening precipitates (Cu-rich ε phase and NbC) during ageing. In the hardened condition, the weld metal reaches a tensile strength of about 930-1030 MPa (135-150 ksi). The electrodes are available in 2.5, 3.2, 4.0, and 5.0 mm diameters, all at 350 mm length, and can be used with AC or DC+ (DCEP) in all welding positions. They are mainly used on 17-4PH, 15-5PH, Custom 450, and Custom 455 base metals and are classified as F-4 under ASME Section IX.

Ageing treatments from H900 (480°C) to H1150 (620°C) let fabricators choose the right balance of strength and toughness for demanding applications in aerospace, nuclear, food processing, petrochemical, and marine industries. Every shipment from Nicorex Alloys includes EN 10204/3.1B mill test certificates, and our facility holds ISO 9001 and ISO 14001 certification.

E630-16 Stainless Steel Electrode Specifications & Classifications

The following specifications and classifications apply to E630-16 coated electrodes for SMAW of precipitation-hardening stainless steels.

AWS A5.4	E630-16
ASME SFA 5.4	E630-16
AMS	5827
UNS (Weld Deposit)	W37410
Polarity	AC or DC+ (DCEP)
Welding Positions	All positions
Electrode Diameters	2.5, 3.2, 4.0, 5.0 mm
Electrode Length	350 mm (14 in.)

The A-Number is not assigned because E630 weld deposit chemistry (17Cr-4.5Ni-3.5Cu) falls outside all twelve A-Number compositions in ASME Section IX Table QW-442. Per QW-404.5, the nominal composition is listed on the WPS/PQR instead.

AWS Classification Breakdown: What Does E630-16 Mean?

Each character in the E630-16 designation has a specific meaning. “E” identifies a flux‑coated SMAW electrode. “630” denotes AISI/UNS Type 630, the standard 17‑4PH precipitation‑hardening stainless steel. “-16” indicates a rutile coating for AC or DC+ (DCEP), usable in all positions with a smooth spray‑type arc.

E630 holds a unique position within AWS A5.4 as the only classification that deposits precipitation-hardenable weld metal. All other SMAW electrodes in A5.4 rely on solid-solution strengthening or martensitic transformation alone. E630 allows further strengthening through post-weld ageing via Cu-rich ε-phase precipitate formation. An E630-15 variant uses a basic coating for DC+ only; AMS 5827 covers both, a cross-reference important for aerospace procurement.

Chemical Composition of E630-16 Weld Deposit (%)

The E630-16 weld deposit replicates the precipitation-hardening capability of 17-4PH base metal. Copper and niobium enable age-hardening through post-weld heat treatment.

Element	C	Cr	Ni	Cu	Nb+Ta	Mo	Si	Mn	P	S
AWS A5.4 Requirement	0.05 max	16.0–16.75	4.5–5.0	3.25–4.00	0.15–0.30	0.75 max	0.75 max	0.25–0.75	0.04 max	0.03 max
Typical (DuraMax)	0.024	16.55	4.76	3.34	0.21	0.04	0.59	0.64	0.023	0.007
Typical (Washington Alloy)	0.037	16.27	4.67	3.52	0.254	0.049	0.52	0.62	0.023	0.011

Copper (3.25-4.0%) is the main element that increases strength. During ageing at 480-620°C, it forms hard Cu-rich (ε-phase) particles. Niobium (0.15-0.30%) gives extra strengthening by forming NbC carbides and also helps make the prior-austenite grains finer. Chromium is kept in a tight range (16.0-16.75%) so the alloy gets the precise precipitation‑hardening behaviour that is required.

All-Weld-Metal Mechanical Properties of E630-16

E630-16 weld deposit properties change significantly with post-weld heat treatment. The table below shows typical values across standard precipitation-hardening conditions.

Property	Tensile Strength	Yield Strength	Elongation	Hardness
As-Welded	924–1030 MPa	850–910 MPa	7–15%	32–38 HRC
PWHT 630°C / 4hr (H1150)	640–700 MPa	500–550 MPa	15–20%	22–28 HRC
Aged 480°C / 4hr (H900)	930–1100 MPa	850–1000 MPa	5–8%	38–44 HRC
AWS A5.4 Minimum	930 MPa (135 ksi)	—	7% min	—

The AWS A5.4 minimum UTS of 930 MPa (135 ksi) applies to the specified heat-treated condition. H900 yields maximum hardness at the cost of ductility; H1150 yields maximum ductility at lower strength. H1025 (550°C/4hr) or H1075 (580°C/4hr) are commonly specified for balanced properties.

Base Metal Compatibility & P-Number Matrix for E630-16

E630-16 is the matching filler for 17-4PH and 15-5PH, depositing weld metal with equivalent precipitation-hardening response.

Base Metal	ASTM Specification	UNS	ASME P-No.	Group
17-4PH (Type 630)	A564 Type 630, A693 Type 630, A705 Type 630	S17400	P-6	4
15-5PH	A564 Type XM-12	S15500	P-6	4
Custom 450	A564 Type XM-25	S45000	P-6	4
Custom 455	—	S45500	P-6	4
PH 13-8Mo	A564 Type XM-13	S13800	P-6	4
Overlay on C-steel	A36, A516	—	P-1 (substrate)	—

For dissimilar joints between 17-4PH and austenitic stainless (304/316), do not use E630-16. Dilution from the austenitic base disrupts precipitation hardening; use E309L-16 or ENiCr-3 instead.

Recommended Welding Parameters for E630-16 Electrode

Diameter-specific welding parameters for E630-16 are listed below.

Diameter (mm)	Diameter (in.)	Current, Flat (A)	Current, Vert/OH (A)	Voltage (V)
2.5	3/32	70-85	65-75	24-28
3.2	1/8	85-110	80-90	26-30
4.0	5/32	110-140	100-120	28-32
5.0	3/16	120-160	110-130	28-32

Preheat is not mandatory for 17-4PH, but 100-150°C is recommended for sections above 25 mm or restrained joints. Maximum interpass temperature is 175°C (350°F) to promote martensitic transformation. For code work, follow the project WPS.

Precipitation-Hardening Heat Treatment Options for E630-16 Weld Deposits

Post-weld ageing determines the final strength-toughness balance of E630-16 deposits. Seven standard conditions are listed below.

Condition	Temperature	Time	Cooling	Typical UTS	Typical HRC
H900	480°C (900°F)	1 hour	Air cool	1030-1100 MPa	40-44
H925	495°C (925°F)	4 hours	Air cool	1000-1070 MPa	38-42
H1025	550°C (1025°F)	4 hours	Air cool	900-970 MPa	33-37
H1075	580°C (1075°F)	4 hours	Air cool	830-900 MPa	30-34
H1100	595°C (1100°F)	4 hours	Air cool	790-860 MPa	28-32
H1150	620°C (1150°F)	4 hours	Air cool	640-720 MPa	22-28
Solution Treat	1040°C (1900°F)	30 min	Air/Oil quench	830-930 MPa	30-35

H900 gives peak strength for wear-resistant fasteners. H1150 gives maximum toughness for pressure-retaining equipment. Solution treated at 1040°C/30 min before ageing for best results. Direct ageing of as-welded deposits may yield inconsistent properties.

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Industrial Welding Applications of E630-16 Coated Electrode

E630-16 is specified wherever a precipitation-hardenable weld deposit with high strength, corrosion resistance, and machinability is required.

Aerospace & Defence: Landing gear components, aircraft structural fasteners, missile parts, and engine mount brackets use 17-4PH weld deposits.
Nuclear Industry: Reactor internals, control rod mechanisms, valve stems, and pump shafts rely on E630-16. Strength, corrosion resistance, and dimensional stability after precipitation hardening suit nuclear service.
Food & Beverage Processing: Brewery vessels, dairy equipment, and high-strength fasteners for food-contact machinery use 17-4PH deposits.
Oil & Gas / Petrochemical: E630-16 suits high-pressure valve and pump parts in H1025 condition, though sour service requires hardness at or below 33 HRC.
Marine & Offshore Platforms: Propeller shaft repair, offshore structural connectors, and seawater-exposed fastener welding benefit from the copper-bearing deposit, which improves chloride corrosion resistance.

Storage, Handling & Re-Drying of E630-16 Coated Electrodes

Store unopened packs in original packaging under dry conditions below 60% RH. After opening, transfer to a holding oven at 100-120°C. The rutile coating is less moisture-sensitive than basic coatings, but limit exposure to 4-8 hours for critical work. Re-dry at 250°C for 60 minutes. Maximum 3 reconditioning cycles. Vacuum-packed electrodes skip initial re-drying.

How to Order E630-16 Welding Rod from Nicorex Alloys

To order E630-16 Welding Rod, follow these 10 important details:

Electrode Type: SMAW; AWS A5.4 / ASME SFA-5.4: E630-16
Size: 2.4 mm, 3.2 mm, 4.0 mm, 4.8 mm; electrodes
Current Type: DCEP or AC
Welding Position: All positions (1G, 2G, 3G, 4G, 6G)
Material Grade: 17-4 PH / 630; UNS S17400; W.Nr. 1.4542; EN ISO 3581-A: E 17 4 PH R
Quantity: Specify the number of cans or the total kg required
Standard: AWS A5.4 / ASME SFA-5.4; EN ISO 3581; ASME Section IX
Documentation: MTC EN 10204 3.1/3.2; PMI Report; Hardness Report; TPI certificate
Packaging: Hermetically sealed metal cans; silica gel desiccant; ISPM 15 export cartons
Delivery Destination: Domestic; specify port or delivery address

Frequently Asked Questions

What precipitation-hardening heat treatments are available for E630-16 Weld Deposits?

E630-16 can be aged from H900 (480°C/1 hr, ~44 HRC) to H1150 (620°C/4 hr, ~24 HRC), with H1025 (~35 HRC) and H1075 (~32 HRC) giving balanced properties, and best response after solution treatment at 1040°C/30 min.

Can the E630-16 Electrode be used to Weld 15-5PH Stainless Steel?

Yes, E630-16 is compatible with 15-5PH, and the post-weld ageing cycle should match the base metal condition.

What is the role of Copper and Niobium in E630-16 Weld Metal?

Copper forms strength-giving Cu-rich precipitates during ageing, while niobium forms NbC carbides and refines grain size for toughness.

Is E630-16 Weld Metal machinable in the Solution-Treated Condition?

Yes, after solution treating at 1040°C/30 min and air cooling to about 28-32 HRC, it machines well with carbide tools.

What is the difference between E630-16 and E630-15 Welding Electrodes?

Both give the same 17Cr-4.5Ni-3.5Cu-0.2Nb weld metal, but E630-16 is rutile-coated for AC/DC+, while E630-15 is basic-coated for DC+ with lower hydrogen and preferred for aerospace.

Does Nicorex Alloys stock ER630 TIG and MIG Wire to match E630-16 Electrodes?

Yes, Nicorex supplies matching ER630 TIG rods (2.4-3.2 mm) and MIG wire (0.9-1.6 mm) per AWS A5.9.

When should the E630-16 Welding Electrode not be used?

Do not use E630-16 for 17-4PH to 304/316 joints, service above 300°C, or sour service above H1150 hardness, and do not substitute it for E410NiMo-16 on CA6NM castings.