A105 STEEL
A105 Steel Bars
The ASTM carbon steel for forged flanges, valve bodies and pipe fittings. We roll it as round bar — hot rolled or cold-drawn bright — ready for your forge shop.
The default steel for forged pressure parts
ASTM A105 covers carbon steel forgings for piping — the flanges, valve bodies, elbows, tees and other fittings that hold pressure at ambient and higher temperatures. It keeps carbon low so it welds and machines without drama, and it upsets and die-forges cleanly. We roll A105 round bar at our own mill near JNPT port from traceable Indian billets, in hot-rolled black or cold-drawn bright condition, so forging shops get consistent input stock with a mill test certificate on every heat.
Equivalent grades
A105 is a forging specification rather than a single international grade, so these are the closest accepted matches rather than exact twins:
Chemical composition
ASTM A105/A105M limits, and the tighter chemistry we maintain (heat analysis):
| wt % | C | Si | Mn | P | S |
|---|---|---|---|---|---|
| ASTM A105 limits | ≤ 0.35 | 0.10–0.35 | 0.60–1.05* | ≤ 0.035 | ≤ 0.040 |
| We maintain | 0.17–0.22 | 0.15–0.30 | 1.00–1.30 | ≤ 0.025 | ≤ 0.025 |
*ASTM A105 permits manganese above 1.05% when carbon is held below the 0.35% maximum (0.06% Mn per 0.01% C, up to 1.35% Mn). Our lower-carbon, higher-manganese balance delivers full strength with better weldability. Residual limits for Cu, Ni, Cr, Mo and V also apply per the standard.
Mechanical properties
| Property | ASTM A105 requirement | Typical as supplied |
|---|---|---|
| Tensile strength | ≥ 485 MPa (70 ksi) | 515–655 MPa |
| Yield strength | ≥ 250 MPa (36 ksi) | 250–300 MPa |
| Elongation | ≥ 22% | 22–25% |
| Brinell hardness | 187 HB max | 140–187 HB |
Indicative per ASTM A105/A105M; actual properties depend on section size and heat treatment, confirmed on the mill test certificate.
Heat treatment
| Process | Typical practice |
|---|---|
| Forging | 950 – 1,250 °C |
| Normalizing | 890 – 940 °C, air cool (the ‘N’ in A105N) |
| Annealing | 870 – 900 °C, slow furnace cool |
| Tempering | ≥ 595 °C where a tempered condition is ordered |
Heat
Soak at ~900–925 °C until through temperature.
Air cool
Still-air cool — normalizing refines the forged grain.
Temper
Where ordered, temper at 595 °C or above.
A105 vs A350 LF2 — what's the difference?
They're companion specifications. Both cover carbon-steel forgings for flanges, valves and fittings, with similar chemistry and the same 485 MPa minimum tensile strength — on paper the two materials look almost identical.
The difference is temperature. A105 is made for ambient and higher-temperature service and is generally limited to −29 °C, while A350 LF2 is impact-tested at −46 °C for cold-climate and low-temperature lines. If your piping sees sub-zero service, see our A350 LF2 steel page.
Sizes & forms we supply
We manufacture A105 in these standard forms and sizes — rounds for flange and fitting forgings, hexagons for forged plugs and bushings. Standard mill lengths are 5–6 m, or we cut to your requirement — see our full size range:
| Form | Size range |
|---|---|
| Rounds | 23.5 mm – 80 mm |
| Bright bars (cold drawn) | 22 mm – 63.5 mm |
| RCS (round-cornered square) | 55 mm, 63 mm, 75 mm |
| Hexagons | 23.5 mm – 52.5 mm |
Finish, certification & ordering
Finishes
Hot rolled (black bar), cold-drawn bright bar, and annealed for easy machining.
Testing & certificate
A heat-wise mill test certificate — chemistry and mechanicals against the heat number — with every consignment. Ultrasonic testing, micro/macro and third-party inspection on request.
Ordering & packing
From about 3 MT per size, several forms in one order, cut to length. Bars are strapped and end-tagged with grade and heat number, packed for road or container export.
Related grades & guides
Forgeability, weldability & machinability
Forgeability
This is what A105 is for — it upsets and die-forges cleanly into flanges and fittings.
Weldability
Welds with standard procedures and common consumables; preheat heavy sections.
Machinability
Cuts cleanly in hot-rolled or normalized condition — hardness is capped at 187 HB.
Applications
Frequently asked questions
What is A105 steel?
What is A105 equivalent to?
Is A105 the same as SA105?
What is A105N?
What is the hardness of A105?
Is A105 weldable?
Can A105 be used at low temperature?
Manufacturer, not a trader
In-house mill
Quality controlled end to end.
Certified
MTC + traceable heats every dispatch.
All forms
Round, bright, hex, RCS in one order.
Export ready
Regular packing for global supply.
Need A105 for your forge shop?
Send us your sizes and quantities and we'll get back with a price.