FOR REQUIREMENT OF THIS GRADE OR FOR DETAIL CONTACT US AT :-

www.ladhanimetal.com

www.ladhanimetal.in

ladhanimetal@gmail.com

info@ladhanimetals.com

Introduction

ISO 630 is the ISO series covering structural steels for hot-rolled flat and long products used principally in welded or bolted structures. The older single-document ISO 630:1995 is withdrawn and has been replaced by a multi-part series. For current specifications, the applicable part of the ISO 630 series should therefore be stated on the purchase order rather than simply referring to the withdrawn ISO 630:1995.

The current Parts 1 to 5 are:

• ISO 630-1:2021 – General technical delivery conditions for hot-rolled products
• ISO 630-2:2021 – Structural steels for general purposes
• ISO 630-3:2021 – Fine-grain structural steels
• ISO 630-4:2021 – High-yield-strength quenched and tempered structural steel plates and wide flats
• ISO 630-5:2023 – Structural steels with improved atmospheric corrosion resistance

These current editions supersede the withdrawn ISO 630-1:2011, ISO 630-2:2011, ISO 630-3:2012, ISO 630-4:2012 and ISO 630-5:2014 editions.

Ladhani Metal Corporation supplies ISO 630 structural steel plates, wide flats, bars and sections in required grades, thicknesses, widths, lengths, delivery conditions and surface conditions.

Applicable Standard

The current ISO 630 series covered in this article consists of:

ISO 630-1:2021 provides the general technical delivery requirements, while the individual Parts 2 to 5 provide the specific requirements for the respective structural steel categories.

Material Type

ISO 630 covers hot-rolled structural steel products including:

• Structural Steel Plates
• Wide Flats
• Hot-Rolled Sections
• Structural Steel Bars
• Fine-Grain Structural Steels
• High-Yield-Strength Structural Steels
• Quenched and Tempered Structural Steels
• Weathering Structural Steels

The series is intended principally for structural products used in welded or bolted construction. ISO 630 does not cover sheet and strip or tubular products, which are addressed through other ISO committees and standards.

Forms of Supply

• Hot-Rolled Steel Plates
• Structural Steel Plates
• Wide Flats
• Flat Bars
• Round Bars
• Square Bars
• Rectangular Bars
• Hot-Rolled Sections
• Structural Sections
• Cut-to-Length Plates
• Custom Cut Plates
• Heavy Structural Plates

ISO 630-1:2021

General Technical Delivery Conditions

ISO 630-1:2021 establishes the general technical delivery conditions applicable to hot-rolled flat and long structural steel products, including plates, sections, wide flats and bars.

It provides the general framework for requirements such as:

• Steelmaking
• Delivery conditions
• Chemical composition
• Mechanical properties
• Surface condition
• Internal soundness
• Dimensions
• Dimensional tolerances
• Testing
• Inspection
• Marking

The specific steel requirements are provided in the other applicable Parts of ISO 630. ISO 630-1:2021 is Edition 2 and was published in April 2021.

ISO 630-2:2021

Structural Steels for General Purposes

ISO 630-2:2021 covers structural steels for general-purpose applications. It applies to steel plates rolled on a reversing mill, wide flats, hot-rolled sections and bars normally supplied in the as-delivered condition and intended principally for welded or bolted structures.

Grades Covered

The current standard contains eight steel grades:

S235 | S275 | S355 | S460 | SG205 | SG250 | SG285 | SG345

The S235, S275, S355 and S460 grades are given in Annex A, while SG205, SG250, SG285 and SG345 are given in Annex B. The available qualities vary by grade.

Thickness Range

For the S-series grades, ISO 630-2:2021 covers:

• S460: 3 mm to 150 mm for long products
• Other principal grades: 3 mm to 250 mm for long products
• Other principal grades: up to 400 mm for flat products

The SG205, SG250, SG285 and SG345 grades have no stated nominal-thickness restriction within the scope of the standard.

ISO 630-3:2021

Fine-Grain Structural Steels

ISO 630-3:2021 covers hot-rolled weldable fine-grain structural steels intended for heavily loaded parts of welded or bolted structures.

The products include:

• Steel Plates
• Wide Flats
• Hot-Rolled Sections
• Bars

The standard covers as-rolled delivery for SG grades, normalized/normalized rolled delivery and thermomechanically processed delivery conditions.

Grades Covered

The current standard covers 13 grades:

S275 | S355 | S390 | S420 | S460 | S500

SG245 | SG290 | SG325 | SG345 | SG365 | SG415 | SG460

Not every grade is available in every quality. Certain qualities include Charpy V-notch impact requirements.

Thickness Range

The standard includes:

• S275N, S355N, S390N, S420N and S460N: up to 250 mm
• S275M, S355M, S390M, S420M, S460M and S500M: up to 150 mm
• SG245, SG325 and SG415: up to 200 mm
• SG345, SG365 and SG460: up to 100 mm
• SG290: up to 40 mm

The minimum nominal thickness specified for the applicable products is 3 mm.

ISO 630-4:2021

High-Yield-Strength Quenched and Tempered Structural Steels

ISO 630-4:2021 specifies technical delivery conditions for high-yield-strength quenched and tempered structural steels.

It applies to:

• Structural Steel Plates
• Wide Flats

The products are supplied in the quenched and tempered condition and are normally intended for welded or bolted structures.

Grades Covered

The current standard covers 10 grades:

S460Q | S500Q | S550Q | S620Q | S690Q | S890Q | S960Q

SG460Q | SG500Q | SG700Q

Not all grades are available in all qualities, and some qualities have Charpy V-notch requirements.

Thickness Range

The current standard specifies:

• S460Q, S500Q, S550Q, S620Q and S690Q: 3 mm to 200 mm
• S890Q and S960Q: 3 mm to 125 mm
• SG460Q and SG500Q: 3 mm to 100 mm
• SG700Q: 3 mm to 150 mm

These thickness limits apply according to the grade and product requirements specified in ISO 630-4:2021.

ISO 630-5:2023

Structural Steels with Improved Atmospheric Corrosion Resistance

ISO 630-5:2023 covers hot-rolled structural steels with improved atmospheric corrosion resistance. These steels are commonly referred to as weathering structural steels.

The standard applies to:

• Steel Plates
• Wide Flats
• Hot-Rolled Sections
• Bars

The products can be supplied in as-rolled, normalized/normalized rolled, thermomechanically processed and quenched and tempered delivery conditions, depending on the grade.

Grades Covered

The current ISO 630-5:2023 includes 14 grades:

S235W | S295W | S355W | S420W | S460W | S500W | S550W

SG245 | SG345 | SG365 | SG400 | SG460 | SG500 | SG700

Additional special grades include S295WP, S355WP and S355WSE within the specific product and thickness limitations of the standard.

Thickness Range

The standard specifies:

• S235W to S550W: up to 150 mm
• SG245 to SG700: up to 200 mm
• S295WP and S355WP plates: up to 20 mm
• S295WP and S355WP wide flats, sections and bars: up to 40 mm
• S355WSE plates: up to 80 mm

These limits are grade- and product-specific.

Mechanical Properties

Mechanical properties depend on the applicable ISO 630 part, grade, quality, product form and nominal thickness.

The principal properties include:

• Yield Strength
• Tensile Strength
• Elongation
• Charpy V-Notch Impact Energy where specified
• Bend Properties where applicable

Typical minimum yield-strength levels range from approximately 235 MPa for general structural grades to 960 MPa for the highest-strength quenched and tempered grade S960Q.

The grade designation generally indicates the nominal minimum yield-strength level, while the quality designation establishes additional requirements such as impact toughness.

Delivery Conditions

Depending on the applicable ISO 630 part and grade, products may be supplied in:

• As-Rolled
• Normalized
• Normalized-Rolled
• Thermomechanically Processed
• Quenched and Tempered

ISO 630-3:2021 specifically covers normalized/normalized rolled and thermomechanically processed conditions, with as-rolled delivery permitted for the specified SG grades.

ISO 630-4:2021 covers quenched and tempered structural plates and wide flats.

ISO 630-5:2023 includes as-rolled, normalized/normalized rolled, thermomechanically processed and quenched and tempered delivery conditions depending on the grade.

Surface Finish

ISO 630 structural steel products can be supplied with suitable hot-rolled surface conditions, including:

• Mill Finish
• Hot-Rolled Surface
• Descaled Surface
• Pickled Surface where specified
• Shot-Blasted Surface where specified
• Cut Edge
• Mill Edge

Surface requirements depend on the product type and applicable standard requirements.

Standard Sizes

ISO 630 structural steel can be supplied in a wide range of dimensions.

• Thickness: According to applicable part and grade
• Width: Standard or custom
• Length: Standard or cut-to-length
• Wide Flats: Various widths and thicknesses
• Bars: Round, square, flat and rectangular
• Sections: Hot-rolled structural sections
• Custom Dimensions: Available by agreement

The maximum applicable thickness varies significantly between ISO 630 Parts and grades.

Key Features

• High structural strength
• Good weldability in appropriate grades
• Suitable for welded structures
• Suitable for bolted structures
• Fine-grain structural options
• High-yield-strength options
• Quenched and tempered grades
• Weathering steel options
• Good impact toughness in specified qualities
• Wide range of plates, wide flats, bars and sections
• Multiple delivery conditions

Applications

Structural Engineering

• Building Structures
• Industrial Structures
• Structural Frames
• Steel Buildings
• Support Structures
• Heavy Fabricated Structures

Bridges and Infrastructure

• Highway Bridges
• Railway Bridges
• Bridge Components
• Infrastructure Structures
• Transportation Structures
• Heavy Structural Fabrication

Heavy Engineering

• Heavy Machinery
• Cranes
• Pressure and Support Structures
• Mining Equipment
• Material Handling Equipment
• Industrial Fabrication

High-Strength Applications

ISO 630-4 grades are used where high yield strength is required while maintaining the specified toughness and fabrication characteristics.

• Heavy Machinery
• Cranes
• Lifting Structures
• Mining Equipment
• High-Strength Structural Frames
• Heavy-Duty Fabricated Components

Weathering Steel Applications

ISO 630-5 grades are intended for structural applications requiring improved atmospheric corrosion resistance.

• Bridges
• Railway Structures
• Architectural Structures
• Outdoor Structural Components
• Infrastructure
• Industrial Structures

Fabrication and Welding

ISO 630 structural steels can generally be cut, drilled, bent, formed and welded using procedures appropriate to the specific grade and thickness.

For higher-strength and fine-grain grades, welding procedures should take into account:

• Carbon Equivalent
• Material Thickness
• Heat Input
• Preheating
• Interpass Temperature
• Welding Consumables
• Hydrogen Control
• Heat-Affected Zone Requirements

The appropriate welding procedure should be established according to the material grade and fabrication requirements.

Heat Treatment

Heat-treatment requirements depend on the ISO 630 part.

General Structural Grades

ISO 630-2 grades are primarily supplied for use in the specified delivery condition rather than requiring subsequent heat treatment.

Fine-Grain Grades

ISO 630-3 includes:

• Normalizing
• Normalized Rolling
• Thermomechanical Processing

Quenched and Tempered Grades

ISO 630-4 grades are supplied in:

• Quenched Condition
• Tempered Condition
• Quenched and Tempered Condition

Weathering Grades

ISO 630-5 includes:

• As-Rolled
• Normalized
• Normalized-Rolled
• Thermomechanically Processed
• Quenched and Tempered

depending on the grade and product.

Advantages

• Wide range of structural steel grades
• General-purpose structural grades
• Fine-grain structural grades
• High-yield-strength grades
• Quenched and tempered grades
• Weathering structural grades
• Good weldability in appropriate grades
• High strength-to-weight potential
• Suitable for heavy fabrication
• Suitable for welded and bolted structures
• Available as plates, wide flats, bars and sections

ISO 630 Current Edition vs Withdrawn Editions

The original ISO 630:1995 covering plates, wide flats, bars, sections and profiles is withdrawn. It should not be presented as the current ISO 630 specification.

The current Parts 1 to 5 are:

ISO's current catalogue lists the older 2011/2012/2014 editions as withdrawn and the 2021/2023 editions as the published versions.

As of September 2026, the 2021 editions of Parts 1–4 and the 2023 edition of Part 5 are the editions to reference for current ISO 630 material specifications. Parts 1–4 have completed their 2026 systematic review process, with ISO's catalogue showing the review outcome as “to be revised”; this does not mean the 2021 editions have already been withdrawn.

Conclusion

ISO 630 is now a multi-part series covering different categories of hot-rolled structural steels rather than a single current standard. The current series includes general-purpose structural steels under ISO 630-2:2021, fine-grain structural steels under ISO 630-3:2021, high-yield-strength quenched and tempered plates and wide flats under ISO 630-4:2021, and atmospheric corrosion-resistant structural steels under ISO 630-5:2023. ISO 630-1:2021 provides the general technical delivery conditions applicable to the series.

Ladhani Metal Corporation supplies ISO 630 structural steel plates, wide flats, bars and sections in required grades, thicknesses, widths, lengths, delivery conditions and surface conditions, with mill test certificates and inspection documentation as required.

FOR REQUIREMENT OF THIS GRADE OR FOR DETAIL CONTACT US AT :-

www.ladhanimetal.com

www.ladhanimetal.in

ladhanimetal@gmail.com

info@ladhanimetals.com

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