Press Brake Forming
Press brake forming for steel: bend radius by grade, tolerances and what a quote needs
Press brake forming bends steel to shape between a punch and a die instead of removing material. What decides whether a design bends cleanly is mostly set before the part reaches the machine: how tight a radius the grade and thickness can take, which way that radius runs relative to the rolling direction, how close a hole or feature can sit to the bend line, and how much the material springs back after the load is released. This page covers those design constraints, plus what a provider needs from you to quote.
What drives the price
- Material thickness
- Steel grade
- Part length and number of bends
- Tolerance requirement
- Tooling setup and die selection
- Total volume
What to send for a quote
- Grade or material number
- Form and dimensions
- A drawing showing bend lines, angles and radii
- Required tolerance
- Quantity
- Whether you need an inspection certificate
- Delivery address and required date
Traceability and EN 10204 certificates
- 2.1
- 2.2
- 3.1
- 3.2
Standard for steel purchases: 3.1
The certificate belongs to the material, not to the bend. Forming does not create an EN 10204 certificate — the real question is whether traceability survives the forming operation, and how each formed part is marked so that it does.
Standard-defined
Source: EN 10204 defines inspection-document types.
Minimum bend radius by grade
| DOMEX 700 | Hot-rolled structural steel · 3 mm · Transverse to rolling direction: 0.8 · Along rolling direction: 0.8 | Supplier-published | Source: SSAB 912en, Table 2 |
|---|---|---|---|
| WELDOX 700 | Quenched structural steel · 8 mm · Transverse to rolling direction: 1.5 · Along rolling direction: 2 | Supplier-published | Source: SSAB 912en, Table 2 |
| WELDOX 900/960 | Quenched structural steel · 8 – 15 mm · Transverse to rolling direction: 3 · Along rolling direction: 4 | Supplier-published | Source: SSAB 912en, Table 2 |
| HARDOX 400 | Wear-resistant plate · 8 mm · Transverse to rolling direction: 2.5 · Along rolling direction: 3 | Supplier-published | Source: SSAB 912en, Table 2 |
| HARDOX 500 | Wear-resistant plate · 20 mm · Transverse to rolling direction: 5.5 · Along rolling direction: 6 | Supplier-published | Source: SSAB 912en, Table 2 |
| DOCOL 600 DP/DL | Cold-rolled high-strength sheet · 0.5 – 2.1 mm · Min. inside radius / thickness (Ri/t), any direction: 0.5 | Supplier-published | Source: SSAB 912en, Table 3 |
| DOCOL 1500 M | Cold-rolled high-strength sheet · 0.5 – 2.1 mm · Min. inside radius / thickness (Ri/t), any direction: 4 | Supplier-published | Source: SSAB 912en, Table 3 |
Rolling direction matters
Figures from a named producer's published tables for its own branded grades. Confirm the achievable radius with your provider for the actual grade, thickness and tooling.
Minimum flange length
A flange shorter than about 4 times the material thickness cannot span the die opening reliably and risks slipping into the die during the stroke.
Supplier-published
Bending near a hole or feature
A hole or cut feature closer than roughly 4 times the material thickness to a bend line sits inside the zone that stretches as the material forms around the bend, and distorts with it.
Indicative
Achievable bend angle tolerance
| Standard tolerance | 1° | ||
|---|---|---|---|
| Achievable with matched bottom-bending tooling | 0.5° |
Supplier-published
Springback
- Higher yield strength
- Larger punch radius
- Wider die opening
- More strain hardening in the material
- Lower friction between plate and tooling — this DECREASES springback, the other four increase it
One producer publishes a rough estimate for its own tested grades: for plate under 10 mm with a die opening of roughly 10 to 12 times the thickness, springback in degrees is approximately the tensile strength in MPa divided by 100. This is that producer's own estimation method for its own grades, not a universal formula.
Supplier-published
Source: SSAB 912en, “Springback” section
Services
What is the minimum bend radius for a press-braked part?
It depends heavily on the grade, and one producer publishes the only clean grade-by-grade table we could source: SSAB's own figures for its Docol, Domex, Hardox and Weldox brands. At the soft end, DOMEX 700 up to 3 mm thick takes a minimum radius of 0.8 times the material thickness. Mid-range, WELDOX 700 under 8 mm needs 1.5 times thickness transverse to the rolling direction, rising to 2.0 times along the rolling direction. At the demanding end, HARDOX 500 over 20 mm thick needs up to 6.0 times thickness along the rolling direction. These are that producer's own figures for its own branded grades — for ordinary structural steel such as S235 or S355 we found no comparably solid published number, so ask your provider what radius they can hold for your specific grade and thickness rather than assume a generic rule.
Does the rolling direction of the steel matter for bending?
Yes. The same sheet bends tighter when the bend line runs across (transverse to) the rolling direction than when it runs along (parallel to) the rolling direction — the published figures above show the along-rolling minimum radius always equal to or larger than the transverse one for the same grade and thickness. If your part allows some freedom in how it is nested on the plate, orienting the bend line across the rolling direction gives the tightest achievable radius.
What bend angle tolerance can I expect?
A standard tolerance of ±1° on bend angles is widely published and achievable on ordinary press brake work. With matched bottom-bending tooling set up for the specific angle, ±0.5° is achievable, at the cost of dedicated tooling and lower throughput. Material thickness variation and the material's own strength affect how repeatable the angle is in practice, so state the tolerance you actually need rather than default to the tightest one.
What is the minimum flange length?
A flange should generally be at least 4 times the material thickness. Shorter than that, the flat edge cannot reliably span the die opening for the full stroke and risks slipping into the die, which ruins the part and can damage the tooling. If your design needs a shorter flange, say so early — it usually means a different tooling approach, not a simple no.
Why does a bend near a hole distort it?
A hole or cut feature that sits closer than roughly 4 times the material thickness to a bend line is inside the zone that stretches as the metal forms around the bend, so it distorts along with it — a round hole can come out egg-shaped. Keep functional features that distance back from any bend line, or expect the provider to flag it and possibly punch or cut them after forming instead of before.
What is springback and how is it handled?
All springback is elastic: the material relaxes slightly back toward flat after the punch releases, so the finished angle opens up a little from the angle it was bent to. It increases with the material's yield strength, with a larger punch radius, and with a wider die opening; it decreases with more friction between the plate and the tooling. One producer publishes a rough estimate for its own tested grades: for plate under 10 mm thickness with a die opening of about 10 to 12 times the thickness, springback in degrees is approximately the tensile strength in MPa divided by 100. That is a starting estimate for that producer's grades and test setup, not a guarantee for any material — the provider compensates by overbending and confirms with a trial piece.
What information do you need for a quote?
Send the grade or material number, the form and dimensions, a drawing showing every bend line, angle and radius, the tolerance you actually need, and the quantity. Say whether you require an inspection certificate, and give the delivery address and the date you need it. A drawing with dimensioned bends turns an enquiry into a firm price rather than a range.
Can I send my own material to be formed?
Providing your own material for forming is common practice, but whether a given shop accepts it — and on what terms regarding liability, offcuts and traceability — varies by provider. Ask before shipping. If the material carries an inspection certificate, ask in the same message how the formed parts will be marked so that traceability survives the bend.
Do I get an EN 10204 3.1 certificate?
EN 10204 defines inspection document types 2.1, 2.2, 3.1 and 3.2, and 3.1 is the usual buyer default in steel procurement. But forming does not create a certificate — it belongs to the material. What matters is whether traceability survives the forming operation, and how each formed part stays linked to its heat. Ask the provider that directly.
Is there a minimum order quantity?
There is no industry-wide minimum order quantity for press brake forming; it varies by provider. Some will form a single piece, others price small quantities in a way that makes them impractical. Ask as part of your enquiry rather than assuming.
What is the lead time?
No general lead time can be stated honestly — it varies by provider, the section, the tooling required, the quantity, and their current load. Ask for a committed date with your quote rather than plan around a generic figure.
What does press brake forming cost?
Press brake forming is not priced from a single rate, so any figure quoted here would mislead. What drives it is material thickness, steel grade, part length and the number of bends, the tolerance you require, the tooling setup and die selection the part needs, and total volume. Send the items in the quote checklist and you will get a firm price instead of a range.
