Nippon Steel SF-3 Flux-Cored Wire

Name: Nippon Steel SF-3 Flux-Cored Wire | Seven Star LLC
Brand: Nippon Steel Welding & Engineering
SKU: SF-3

Seamless rutile cored wire for low-temperature toughness

The Nippon Steel SF-3 is a rutile-type seamless flux-cored wire for CO2-shielded welding, classified AWS A5.20 E71T-12C-H4 and JIS Z 3313 T492T1-1CA-N1-UH5. Nippon Steel Welding & Engineering designed it for shipbuilding grade E steel: the weld metal shows excellent toughness in the -20 to -30 °C range, with good crack resistance and all-position weldability.

Applications are mild steel and 490 MPa high tensile steel for machinery, structures, steel frames, ships, bridges, towers, rolling stock and parts where toughness is especially important.

Technical specifications

Parameter	Specification
Manufacturer / product	Nippon Steel Welding & Engineering / SF-3
Process	FCAW, gas-shielded, seamless rutile wire
AWS classification	A5.20 E71T-12C-H4
JIS classification	Z 3313 T492T1-1CA-N1-UH5
Shielding gas	CO2
Polarity	DC (+)
Typical weld metal, %	C 0.05, Si 0.42, Mn 1.30, P 0.013, S 0.004, Ni 0.44
Typical mechanical properties	YS 545 MPa, TS 600 MPa, El. 27%
Charpy V-notch	105 J at -30 °C; 130 J at -20 °C
Current, 1.2 mm	Flat and horizontal fillet 180–300 A; horizontal 180–300 A; V-up and overhead 180–260 A
Current, 1.4 mm	Flat and horizontal fillet 200–410 A; horizontal 200–350 A; V-up and overhead 180–260 A
Nozzle to base metal distance	Within 20 mm

Where SF-3 fits against a general-purpose E71T-1C

The main difference from the general-purpose Nippon Steel SF-1 is the small nickel addition and the -12 designation, which in AWS A5.20 calls for tighter manganese limits and Charpy testing at -30 °C. That makes SF-3 the choice when a ship classification grade or project specification demands low-temperature impact values that a standard rutile wire may not reliably meet.

Being seamless, the wire keeps a low diffusible hydrogen level (H4) and does not pick up moisture through a seam during storage, an advantage on humid sites.

Usage guidelines from the handbook

Toughness depends on good gas cover. If shielding is insufficient, nitrogen from the air enters the weld and degrades toughness, so keep the nozzle within 20 mm of the base metal and protect the arc from draughts. Select heat input according to plate thickness and position; higher heat input lowers impact values. For one-side welding, the manufacturer recommends the SB-41 backing material. Other handling notes follow the SF-1 guidelines: looser feed roll pressure than for solid wire and slightly lower arc voltage.

The two published diameters suit different work. The 1.2 mm wire covers all positions with the same 180–260 A range in vertical-up and overhead, so one setting works for most positional joints in a ship block. The 1.4 mm wire extends the flat and horizontal fillet range to 410 A for higher deposition on downhand seams, while staying usable at 180–260 A out of position.

Documents and quotation

The manufacturer handbook page is attached to this page. Browse our Flux-Cored Welding Wire category for related consumables.

For a quotation, send the diameter, spool weight, quantity and any classification society approval or mill certificate requirement.

Nippon Steel Welding & Engineering is a Japanese maker of welding consumables, welding machines and plasma equipment, headquartered in Tokyo. The current company was formed on July 1, 2002 and is a wholly owned subsidiary of Nippon Steel Corporation, with roots in welding rod makers established as early as 1934. It sells its welding materials under the WELDREAM brand. Welding materials from Nippon Steel Welding & Engineering The consumables program covers flux-cored wires, covered electrodes, submerged arc wire and flux combinations, and solid MIG/MAG and TIG wires. The company states that it is the first and only Japanese manufacturer to mass-produce seamless flux-cored wire, made since 1981, which it recommends for low-temperature and high-tensile applications. It also produces plasma welding and cutting equipment and metal tube optical fibre cables. Ordering Nippon Steel welding consumables: what we need Give the product name, for example SF-1, the classification in your procedure, the wire diameter and spool or package, and the quantity. Seven Star LLC, an independent supplier in Muscat, checks the grade against the manufacturer's catalogue page and can provide the datasheet and the certificates issued with the order on request.

Frequently Asked Questions