Hot Forging
Hot forging deforms steel above its recrystallisation temperature, typically 1100–1250°C, where flow stress collapses and the metal can be pushed into complex shapes in very few blows. It is the workhorse route for almost every structural steel forging we ship.
- Working Temperature
- 1100 – 1250 °C
- Heating Method
- Induction, pyrometer controlled
- Typical Surface Finish
- Ra 12.5 – 25 µm as forged
- Grain Structure
- Refined, recrystallised
- Suitable Materials
- Carbon, alloy, micro-alloyed, stainless
- Best For
- Complex shapes, medium to high volume
Hot Forging at a glance
Quotable facts from Avadh Techno Forge, Gundasara, Gondal, Rajkot.
- Working Temperature: 1100 – 1250 °C
- Heating Method: Induction, pyrometer controlled
- Typical Surface Finish: Ra 12.5 – 25 µm as forged
- Grain Structure: Refined, recrystallised
- Suitable Materials: Carbon, alloy, micro-alloyed, stainless
- Best For: Complex shapes, medium to high volume
Temperature Control Is the Whole Game
Too cold and the die loads spike, corners under-fill and cracks start at the flash line. Too hot and grain grows coarse and the surface decarburises. Our induction heaters hold billets in a narrow band monitored by infrared pyrometer, with heat numbers and temperature logs recorded batch by batch.
- Induction heating, not open-hearth guesswork
- Pyrometer verification before every strike
- Scale control by short soak times
- Recorded traceability per heat number
Complex Geometry in Fewer Operations
Hot flow lets a single blocker and finisher sequence produce ribs, bosses, forked ends and deep webs that cold forging simply cannot fill. That means fewer operations, less tooling and a lighter machining envelope on parts such as yokes, levers, knuckles and hubs.
Post-Forging Metallurgy
Controlled cooling on conveyors, or a normalising cycle where the drawing calls for it, delivers a uniform ferrite-pearlite or tempered structure. Micro-alloyed grades can be air cooled to strength directly from forging heat, cutting cost and cycle time on high-volume automotive parts.
Hot Forging Temperature Windows by Material
Temperature is the variable that touches every outcome in hot forging: how easily metal flows, how much scale forms, how long the die lasts and what grain size the part ends up with. Each material has a usable window, and the finish temperature matters as much as the start temperature — finishing too cold cracks the part, finishing too hot coarsens the grain.
| Material | Working range | Particular care |
|---|---|---|
| Carbon steels (EN8, SAE 1045) | ≈ 1,100 – 1,250 °C | Wide, forgiving window |
| Low alloy steels (EN19, EN24) | ≈ 1,050 – 1,200 °C | Control finish temperature |
| Case hardening steels (20MnCr5) | ≈ 1,050 – 1,200 °C | Finish temperature affects later case depth |
| Austenitic stainless (SS 304, 316) | ≈ 1,150 – 1,250 °C | Finish above ≈ 950 °C or it cracks |
| Bearing steel (EN31) | ≈ 1,050 – 1,150 °C | Avoid network carbides on cooling |
| Aluminium alloys | ≈ 400 – 480 °C | Narrow window; die temperature critical |
What Heat Costs: Scale, Decarburisation and Die Life
Heat makes metal flow, and it also takes something back. Scale — iron oxide forming on the hot surface — costs typically 1–3% of billet weight, abrades dies and leaves pits if pressed into the surface. Decarburisation burns carbon out of the surface layer, leaving a skin that will not harden properly. Both worsen with soak time, which is the practical argument for induction heating over long furnace soaking: the billet reaches temperature quickly and spends less time there.
- Scale loss typically 1–3% of billet weight
- Decarburised layer must be removed by machining allowance
- Die life falls sharply if billets run cold
- Short induction soak limits both scale and decarburisation
How We Control Hot Forging Temperature
Every billet is induction heated and verified by infrared pyrometer before it is struck, with temperature logged against the batch and heat number. Dies are preheated before production so the first parts are not struck into cold tooling, which would thermally shock the die surface and start the crazing network that becomes thermal fatigue cracking. Die lubricant is applied every stroke. Where a part needs deformation to reach the core of a heavy section, it runs on a press rather than a hammer — see drop forging versus press forging.
People also ask
Why is hot forging preferred for complex shapes?
Above recrystallisation temperature the metal never work hardens, so ribs, forks and deep webs fill in a few blows without cracking or intermediate annealing.
How is forging temperature controlled?
Induction heating with infrared pyrometer verification before each strike, with temperature logged against the batch and heat number.
Topics covered on this page
- hot forging manufacturer India
- hot forged components supplier
- hot forging process India
- hot forging company Rajkot
Based on work carried out at our own forging plant at Gundasara, Gondal, Rajkot — operating since 2008.
Questions Answered
What is the difference between hot forging and cold forging?
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Hot forging works above recrystallisation temperature so the steel flows easily into complex shapes with no work hardening. Cold forging runs at room temperature, giving tighter tolerances and a better finish but only on simpler geometry.
Does hot forging cause decarburisation?
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It can if soak times are long. We control it with short induction heating cycles and, where the specification is strict, a machining allowance that removes the affected surface layer entirely.
Which parts are best suited to hot forging?
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Yokes, levers, steering knuckles, connecting rods, crankshafts, flanges, hubs and any component with ribs, forks or deep cavities that need free metal flow.
Is hot forging suitable for stainless steel?
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Yes. SS 304, SS 316 and SS 410 are hot forged in a tighter temperature window with careful finish temperature control to avoid sensitisation and cracking.