ISO/DIS 20805
ISO/TC 17/SC 12
Secretariat: JISC
Date: 2025-12-08
Hot-rolled steel sheet in coils of higher yield strength with improved formability and heavy thickness for cold forming
Tôles fortes en acier laminées à chaud à limite d'élasticité et aptitude au formage accrues, en bobines, pour formage à froid
DIS stage
Warning for WD’s and CD’s
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Contents
Dimensional and shape tolerances
Information to be supplied by the purchaser
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This document was prepared by Technical Committee ISO/TC 17, Steel, Subcommittee SC 12, Continuous mill flat rolled products.
This fourth edition cancels and replaces the third edition (ISO 20805:2017), which has been technically revised. The following changes have been made:
Hot-rolled steel sheet in coils of higher yield strength with improved formability and heavy thickness for cold forming
1.0 Scope
This document specifies the requirement for continuous hot-rolled steel sheet in coils of higher yield strength with improved formability and heavy thickness for cold forming.
As a result of the combination of higher strength and improved formability, it is possible to obtain savings in mass along with better weldability.
The product is intended for applications where parts are to be fabricated requiring better formability than is provided by normal high-yield-strength steel sheet.
The steel sheet is produced in a number of grade designations designed to be compatible with differing application requirements.
This document does not apply to:
- steels intended for boilers or pressure vessels,
- steels designated as commercial quality, drawing quality or structural quality,
- steels rolled to cold-reduced products,
- steels designated as weathering steels, having increased atmospheric corrosion resistance,
- steel rolled on a plate mill.
2.0 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 148-1, Metallic materials — Charpy pendulum impact test — Part 1: Test method
ISO 6892-1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature
3.0 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
- IEC Electropedia: available at https://www.electropedia.org/
- ISO Online browsing platform: available at https://www.iso.org/obp
microalloying elements
elements, such as niobium, vanadium, titanium, etc., added singly or in combination to obtain higher strength levels combined with better formability, weldability and toughness as compared with non-alloyed steel produced to equivalent strength levels
hot-rolled steel sheet in coils
steel sheet in coil form manufactured through hot-rolling process, where the material was heated before rolling to achieve the required sheet thickness and tolerances
Note 1 to entry: The product has a surface covered with oxide or scale resulting from the hot-rolling operation.
hot-rolled descaled steel sheet in coils
hot-rolled steel sheet in coils (3.2), from the surface of which oxide or scale has been removed, commonly by pickling in an acid solution
Note 1 to entry: This product is normally supplied oiled.
Note 2 to entry: Descaling may also be performed by mechanical methods such as grit blasting.
mill edge
normal edge without any definite contour produced in hot-rolling
Note 1 to entry: Mill edges may contain some irregularities such as cracked or torn edges or thin (feathered) edges.
sheared edge
normal edge obtained by shearing, slitting or trimming a mill-edge product
Note 1 to entry: Normal processing does not necessarily provide a definite positioning of the slitting burr.
lot
specified quantity of steel sheet of the same grade rolled to the same thickness and condition
edge camber
greatest deviation of a side from a straight line, the measurement being taken on the concave side with a straight edge
4.0 Dimensions
The product is commonly produced in the range of thicknesses greater than 6 mm to 25 mm, and widths of 600 mm and over, in coils. Hot-rolled sheet less than 600 mm wide can be slit from wide sheet and will be considered as sheet.
5.0 Conditions of manufacture
5.1 Steelmaking
Unless otherwise agreed upon by the interested parties, the processes used in making the steel and in manufacturing hot-rolled sheet are left to the discretion of the manufacturer. On request, the purchaser shall be informed of the steelmaking process being used.
5.1.1 Chemical composition
The chemical composition (heat analysis) shall conform to the requirements in Table 1 and Table 2.
The steel covered by this document shall contain microalloying elements. The chemical composition may be agreed between the interested parties at the time of enquiry and ordering.
Table 1 — Chemical analysis (heat analysis)
Mass fractions in percent
All grades | C | Mn | P | S | Si |
|---|---|---|---|---|---|
0,15 max. | EN 10149-22,2 max. | 0,025 max. | GB/T 15910,025 max. | EN 10149-20.5 max. | |
As the form of sulfide inclusions may have a certain influence on the cold-forming properties of the products, the manufacturers may, at their discretion, influence the form of inclusions by adding certain elements, such as Ce or Ca, or may choose a very low sulfur content for these steels. These steels shall also contain one or more of the following elements: V, Ti or Nb. When used singly or in combination, these elements shall be present at a minimum level of 0,005 %. Other alloying elements may be present, but are not required. | |||||
Table 2 — Limits on additional chemical elements
Mass fractions in percent
Cu, max. | Heat analysis Product analysis | GB/T 15910,30 0,35 |
Ni, max. | Heat analysis Product analysis | GB/T 15910,30 0,35 |
Cr, max. | Heat analysis Product analysis | GB/T 15910,20 0,25 |
Mo, max. | Heat analysis Product analysis | GB/T 15910,10 0,11 |
NOTE The sum of copper, nickel, chromium and molybdenum shall not exceed 0,70 % on heat analysis. When one or more of these elements are specified, the sum does not apply, in which case, only the individual limits on the remaining elements apply. | ||
5.1.2 Chemical analysis
5.1.3 Heat analysis
An analysis of each sheet shall be made by the manufacturer in order to determine compliance with the requirements given in Table 1 and Table 2. On request, a report of the heat analysis shall be made available to the purchaser or the purchaser’s representative. Each of the elements listed in Table 1 and Table 2 shall be included in the report of the heat analysis. When the amount of copper, nickel, chromium or molybdenum present is less than 0,02 % the analysis may be reported as “< 0,02 %”.
5.1.4 Product analysis
A product analysis may be made by the purchaser in order to verify the specified analysis of the product. The product analysis tolerance and limits on additional chemical elements shall be in accordance with Table 2 and Table 3.
5.2 Mechanical properties
At the time that the steel is made available for shipment, the mechanical properties shall be as given in Table 4, when they are determined on test pieces in accordance with the requirements of Clause 7. Any additional property requirements specified or required are subject to agreement between the interested parties at the time of enquiry and ordering.
Table 3 — Product analysis tolerances from Table 1
Mass fraction in percent
Element | Maximum or range of specified | Tolerance over maximum specified |
|---|---|---|
C | ≤ 0,15 | 0,03 |
Mn | ≤0.80 | 0,03 |
> 0.80 to ≤ 2,2 | 0.05 | |
P | ≤ 0,025 | 0,010 |
S | ≤ 0,025 | 0,010 |
Si | ≤0.37 | 0.03 |
> 0.37 to ≤ 0.50 | 0.05 | |
NOTE The above maximum tolerance is the allowable excess over the requirement of heat analysis shown in Table 1. For example, for all grades in this document, the following product analysis values are within these tolerances: C 0,18 %, Mn 2.25%, P 0,035 %, S 0,035 %, Si 0,55%. | ||
Table 4 — Mechanical properties
ReH | Rm | Aa min. % | ||||
|---|---|---|---|---|---|---|
Grade | min. b | min. | Lo = 5,65 | Lo = 50 mm for sheet thickness | ||
MPa c | MPa c | 6 mm < t ≤ 12 mm | 12 mm < t ≤ 19 mm | 19 mm < t ≤ 25 mm | ||
325 | 325 | 410 | 19 | 21 | 24 | 26 |
355 | 355 | 420 | 18 | 20 | 23 | 25 |
390 | 390 | 450 | 17 | 19 | 21 | 23 |
420 | 420 | 480 | 15 | 17 | 19 | 21 |
490 | 490 | 540 | 12 | 13 | 16 | 17 |
560 | 560 | 610 | 9 | 10 | 12 | 13 |
EN 10149-2600 | 600 | 700 | 8 | 9 | 11 | 12 |
EN 10149-2650 | 650 | 750 | 7 | 8 | 9 | 11 |
EN 10149-2700 | 700 | 800 | 6 | 7 | 8 | 10 |
EN 10149-2800 | 800 | 950 | 5 | 6 | 7 | 8 |
ReH = upper yield strength Rm = tensile strength A = percentage elongation after fracture Lo = gauge length of original test piece So = original cross-sectional area of gauge length, in square millimetres t = thickness of steel sheet in mm a In case of dispute, only the results obtained on a 50 mm test piece will be valid b The yield strength values can be measured by 0,5 % total elongation proof stress(proof stress under load) or by 0,2 % offset when a definition yield phenomenon is not present.. c 1 MPa = 1 N/mm2. | ||||||
5.2.1 Application
It is desirable that hot-rolled steel sheet be identified for fabrication by the name of the part or by the intended application. Proper identification of the part may include visual examination, prints or description, or a combination of these.
5.2.2 Weldability
The product is normally suitable for welding if appropriate welding conditions are selected. For non-descaled steel, it may be necessary to remove the scale or oxide depending upon the welding method.
5.2.3 Surface condition
The designation AR describes the as-rolled condition. Oxide or scale on hot-rolled steel sheet is subject to variations in thickness, adherence and colour. Removal of the oxide or scale by pickling or blast cleaning may disclose surface imperfections not readily visible prior to this operation. The steel shall be supplied as-rolled (3.2) or descaled (3.3) and oiled, as requested by the purchaser at the time of enquiry and ordering. If neither condition is specified, the delivery will be as-rolled.
5.2.4 Oiling
The designation DO describes the descaled and oiled condition. As a deterrent to rusting, a coating of oil is usually applied to hot-rolled descaled steel sheet. The oil is not intended as a drawing or forming lubricant and shall be easily removable with degreasing chemicals. On request, the manufacturer shall advise the purchaser of the type of oil that has been used. Hot-rolled descaled steel sheet may be ordered not oiled, if required, in which case the supplier has limited responsibility if oxidation occurs.
6.0 Dimensional and shape tolerances
Dimensional and shape tolerances applicable to hot-rolled steel sheet in coils of structural quality and heavy thickness shall be in accordance with Table 5 and Table 6. These tolerances also apply to descaled material.
Edge camber shall not exceed 25 mm in any 5 000 mm of length (see Figure 1).
Table 5 — Thickness tolerances for heavy thickness hot-rolled sheet (including descaled) in coils
Dimensions and tolerances in millimetres
Specified widths | Thickness tolerances for specified thicknessesa | ||||
|---|---|---|---|---|---|
6,00 < t ≤ 8,00 | 8,00 < t ≤ 10,00 | 10,00 < t ≤ 12,50 | 12,50 < t ≤ 16,00 | 16,00 < t ≤ 25,00 | |
600 ≤ w ≤ 1 200 | ±0,29 | ±0,32 | ±0,35 | ±0,38 | ±0,40 |
1 200 < w ≤ 1 500 | ±0,30 | ±0,33 | ±0,36 | ±0,39 | ±0,42 |
1 500 < w ≤ 1 800 | ±0,31 | ±0,34 | ±0,37 | ±0,40 | ±0,44 |
w > 1 800 | ±0,35 | ±0,40 | ±0,43 | ±0,48 | ±0,50 |
w = width in mm t = thickness in mm The values specified do not apply to the uncropped ends for a length, l, of a mill-edge coil. The length, l, would be calculated using the following formula: provided that the result was not greater than 20 m inclusive of both ends. a Thickness tolerances shall be applied the area on the sheet not less than 40 mm from a side edge for mill-edge material and not less than 25 mm from the edge for sheared material. | |||||
Table 6 — Width tolerances for heavy-thickness hot-rolled sheet in coils
Dimensions and tolerances in millimetres
Specified widths | Mill edges | Sheared edges | ||
|---|---|---|---|---|
600 ≤ w ≤ 1 200 | +28 | −0 | +5 | −0 |
1 200 < w ≤ 1 500 | +38 | −0 | +6 | −0 |
1 500 < w ≤ 1 800 | +45 | −0 | +8 | −0 |
w > 1 800 | +50 | −0 | +10 | −0 |
w = width | ||||
Key
1 edge camber
2 side edge (concave side)
3 straight edge
Figure 1 — Measurement of edge camber
7.0 Sampling — Tensile test
One representative sample for the tensile test required in Table 4 shall be taken from each lot 50 t or less of sheet for shipment.
8.0 Mechanical property tests
8.1 Tensile test
The tensile test shall be carried out in accordance with ISO 6892-1. Transverse test pieces shall be taken mid-way between the centre and edge of the sheet as-rolled.
8.1.1 Impact test
While not usually specified, if so agreed at the time of ordering, impact tests may be specified for material ordered according to this document. The test piece shall be taken in the longitudinal direction and the test shall be carried out in accordance with ISO 148-1. Material less than 11 mm in thickness will result in sub-size impact tests.
9.0 Retests
9.1 Machining and flaws
If any test piece shows defective machining or develops flaws, it shall be discarded and another piece substituted.
9.1.1 Elongation
If the percentage of elongation of any test piece is less than that specified in Table 4 and if any part of the fracture is outside the middle half of the gauge length as scribed before the test, the test shall be discarded and a retest shall be carried out.
9.1.2 Additional tests
If a test does not give the specified results, two more tests shall be carried out at random on the same lot. Both retests shall conform to the requirements of this document; otherwise, the lot shall be rejected.
10.0 Resubmission
The manufacturer may resubmit for acceptance the products that have been rejected during earlier inspection because of unsatisfactory properties, after the rejected products have been subjected to a suitable treatment (e.g. selection, heat treatment), which, on request, will be indicated to the purchaser. In this case, the tests shall be carried out as if they applied to a new batch.
The manufacturer has the right to present the rejected products to a new examination for compliance with the requirements for another grade.
11.0 Workmanship
The surface condition shall be that normally obtained in a hot-rolled or hot-rolled descaled product.
The steel sheet in cut lengths shall be free from laminations, surface flaws and other imperfections that are detrimental to subsequent appropriate processing.
Processing for shipment in coils does not afford the manufacturer the opportunity to observe readily or to remove imperfect portions, as can be carried out on the cut-length product. However, this does not relieve the manufacturer of the responsibility to provide a product that meets the requirement for surface condition that is normally obtained in a hot-rolled or hot-rolled descaled product.
12.0 Inspection and acceptance
While not usually required for products covered by this document, when the purchaser specifies that inspection and tests for acceptance be observed prior to shipment from the manufacturer’s works, the manufacturer shall afford the purchaser’s inspector all reasonable facilities to determine that the steel is being furnished in accordance with this document.
Steel that is reported to be defective after arrival at the user’s works shall be set aside, properly and correctly identified and adequately protected. The manufacturer shall be notified in order that they may properly investigate.
13.0 Coil size
When hot-rolled steel sheet in accordance with this document is ordered in coils, a minimum inside diameter (ID) or range of acceptable inside diameters shall be specified. In addition, the maximum outside diameter (OD) and the maximum acceptable coil mass shall be specified.
14.0 Marking
Unless otherwise stated, the following minimum requirements for identifying the steel shall be legibly stencilled on the top of each lift, or shown on a tag attached to each coil or shipping unit:
- the manufacturer’s name or identifying brand;
- a reference to this document, i.e. ISO 20805:;
- the grade designation;
- the order number;
- the product dimensions;
- the mass;
- the coil number;
- production date.
15.0 Information to be supplied by the purchaser
To adequately specify requirements according to this document, enquiries and orders shall include the following information:
- a reference to this document, i.e. ISO 20805:;
- the name, quality and grade of the material (for example, hot-rolled steel sheet, higher yield strength with improved formability, grade 355);
- the dimensions of the product and the quantity required;
- the application (name of part) if possible (see 5.5);
- whether pickling or descaling by grit or shot blasting is required (material so specified will be oiled unless ordered not oiled) (see 3.3);
- the type of edge (see 3.4 and 3.5);
- whether cropped ends are required;
- the report of the mechanical properties and/or the heat analysis, if required (see 5.3.1 and 5.4);
- limitations on masses and dimensions of individual coils , if applicable (see Clause 13);
- inspection and tests for acceptance prior to shipment from the manufacturer’s works, if required (see Clause 12);
EXAMPLE A typical ordering description is as follows:
ISO 20805: hot-rolled steel sheet of higher yield strength with improved formability, grade 355, 1 200 mm × 2 440 mm × coil, 40 000 kg, for Part No. 54321, descaled and oiled (DO), edge trimmed, furnish report of mechanical properties, maximum coil 15 000 kg, ID 760 mm, OD 1 850 mm.
[1] EN 10149-2:2013, Hot-rolled flat products made of high yield strength steels for cold forming
[2] GB/T 1591:2018, High strength low alloy structural steels
