IS 432 Part 1 : 1982Mild Steel and Medium Tensile Steel Bars and Hard-Drawn Steel Wire for Concrete Reinforcement - Part 1: Mild Steel and Medium Tensile Steel Bars

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ASTM A615/A615M · ISO 6935-1 · AS/NZS 4671

CurrentRareSpecificationStructural Engineering · Steel and Reinforcement

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IS 432:1982 Part 1 is the Indian Standard (BIS) for mild steel and medium tensile steel bars and hard-drawn steel wire for concrete reinforcement - part 1: mild steel and medium tensile steel bars. This code specifies the manufacturing, chemical, and mechanical requirements for mild steel (Grade I and II) and medium tensile steel bars used as concrete reinforcement. While largely superseded in everyday practice by deformed TMT bars (IS 1786), it remains the active specification for plain Fe 250 reinforcement bars.

Specifies requirements for mild steel and medium tensile steel bars used as reinforcement in concrete, commonly superseded by IS 1786 for new designs.

Quick Reference — IS 432 Part 1:1982 Plain Bar Properties

Grade I (Fe250) and Grade II (Fe350) plain mild-steel and medium-tensile bars — yield, UTS, elongation, bend, mass tolerance and chemistry.

✓ Verified 2026-04-26

Reference	Value	Clause
Grade I (mild steel) — yield stress (min)	250 MPa (≤20 mm) / 240 MPa (>20–50 mm)	Cl. 5 (Table 1)
Grade II (medium tensile) — yield stress (min)	350 MPa (≤20 mm) / 340 MPa (>20–50 mm)	Cl. 5 (Table 1)
Grade I — ultimate tensile strength (min)	410 MPa	Cl. 5 (Table 1)
Grade II — ultimate tensile strength (min)	540 MPa	Cl. 5 (Table 1)
Grade I — elongation (min, gauge 5.65√A)	23 %	Cl. 5 (Table 1)
Grade II — elongation (min)	20 %	Cl. 5 (Table 1)
Bend test — Grade I bars ≤25 mm	180° around 2 φ mandrel	Cl. 6 (Table 2)
Bend test — Grade I bars >25 mm	180° around 3 φ mandrel	Cl. 6 (Table 2)
Bend test — Grade II bars ≤25 mm	180° around 3 φ mandrel	Cl. 6 (Table 2)
Bend test — Grade II bars >25 mm	180° around 4 φ mandrel	Cl. 6 (Table 2)
Standard nominal sizes — plain round bars	6, 8, 10, 12, 16, 20, 22, 25, 28, 32, 36, 40, 45, 50 mm	Cl. 4 (Table 3)
Mass tolerance — bars 6–10 mm	± 7 % per length	Cl. 7
Mass tolerance — bars 12–16 mm	± 5 %	Cl. 7
Mass tolerance — bars ≥20 mm	± 3.5 %	Cl. 7
Carbon (max) — Grade I	0.23 %	Cl. 4 (Table 1)
Sulphur + Phosphorus (max) — Grade I	0.055 % each (S ≤ 0.055, P ≤ 0.055)	Cl. 4 (Table 1)
Carbon (max) — Grade II	0.25 %	Cl. 4 (Table 1)
Length tolerance — exact-length bars	± 25 mm (typical) / +75, −25 over 12 m	Cl. 8
Standard length — bars supplied	5–13 m (typically 12 m)	Cl. 8
Application — RCC use status	Largely superseded by IS 1786 HYSD/TMT for RCC	see IS 456 Cl. 5.6

⚠ Plain bars are now used mainly for stirrups/ties and ancillary work. RCC main reinforcement uses IS 1786. Verify against latest BIS amendments.

Overview

Status: Current
Usage level: Rare
Domain: Structural Engineering — Steel and Reinforcement
Type: Specification

International equivalents

ASTM A615/A615M-22 · ASTM International, United States ISO 6935-1:2019 · International Organization for Standardization, International AS/NZS 4671:2019 · Standards Australia / Standards New Zealand, Australia/New Zealand

Typically used with

IS 226 IS 228 IS 1599 IS 1608 IS 2062

Also on InfraLens for IS 432

6Key values 3Tables 3FAQs

Practical Notes

! Mild steel (Fe 250) plain bars are rarely used as main reinforcement in modern structural concrete, but they are still preferred for lifting hooks, dowel bars, and ties where high ductility and bendability are required.

! Engineers must check the rolling tolerances on mass per meter during site material testing, as negative mass deviations beyond the permissible limit compromise the cross-sectional area.

Frequently referenced clauses

Cl. 4Chemical Composition Cl. 6Tensile Test Cl. 7Bend Test Cl. 9Tolerances on Dimensions and Nominal Mass

mild steelmedium tensile steelreinforcementFe 250

International Equivalents

Similar International Standards

ASTM A615/A615M-22ASTM International, United States

HighCurrent

Standard Specification for Deformed and Plain Carbon-Steel Bars for Concrete Reinforcement

Covers plain carbon-steel bars (Grade 40 [280]) with mechanical properties similar to IS 432's Grade I (Fe 250).

ISO 6935-1:2019International Organization for Standardization, International

HighCurrent

Steel for the reinforcement of concrete — Part 1: Plain bars

Specifically addresses plain reinforcing bars, with grade RB300 being a close functional match to the grades in IS 432.

AS/NZS 4671:2019Standards Australia / Standards New Zealand, Australia/New Zealand

HighCurrent

Steel for the reinforcement of concrete

Includes Class L plain round bars (Grade R250N) with a specified yield strength of 250 MPa, directly matching IS 432 Grade I.

BS 4449:1997BSI, United Kingdom

HighWithdrawn

Specification for carbon steel bars for the reinforcement of concrete

This historical standard included a Grade 250 for plain round bars, which was a direct equivalent to IS 432's Grade I.

Key Differences

≠IS 432:1982 is a prescriptive standard focused on specific grades (Fe 250, Fe 350). Modern international standards like EN 10080 or BS 4449 are more performance-based, specifying ductility classes (e.g., A, B, C) and relying on characteristic strength values derived statistically.

≠Weldability in IS 432:1982 is controlled by simple maximum limits on Carbon, Sulphur, and Phosphorus. Most modern standards use a Carbon Equivalent Value (CEV) formula to provide a more accurate assessment of weldability.

≠IS 432 covers only low-strength plain and medium-tensile bars. Most current international standards (e.g., ASTM A615, BS 4449) primarily focus on high-strength deformed (ribbed) bars (e.g., 500 MPa grades), with plain mild steel being a minor or legacy product.

≠Ductility in IS 432 is measured solely by percentage elongation after fracture. Modern standards often require additional ductility metrics, such as the ratio of tensile strength to yield strength (Rm/Re) and elongation at maximum force (Agt).

Key Similarities

≈All standards mandate fundamental mechanical testing, including a tensile test to determine yield strength, ultimate tensile strength, and elongation, as a primary means of quality control.

≈The requirement for a bend test, where a bar is bent 180 degrees around a specified mandrel diameter without fracture or cracking, is a common feature for assessing the soundness and ductility of the steel.

≈Despite a general shift to high-strength deformed bars, several key international standards (ASTM A615, ISO 6935-1, AS/NZS 4671) retain specifications for plain, round, low-strength bars similar in concept to those in IS 432.

≈All compared standards specify permissible manufacturing tolerances on the nominal mass per metre or nominal diameter of the bars to ensure consistency in construction.

Parameter Comparison

Parameter	IS Value	International	Source
Minimum Yield Strength (Mild Steel Grade)	250 MPa (for Grade I / Fe 250)	250 MPa (for Grade R250N)	AS/NZS 4671:2019
Minimum Ultimate Tensile Strength (UTS)	410 MPa (for Grade I / Fe 250)	420 MPa (for Grade 40 [280])	ASTM A615/A615M-22
Minimum Elongation (on 5.65√A gauge length)	23% (for Grade I / Fe 250)	22% (for Grade RB300)	ISO 6935-1:2019
Maximum Carbon (C) Content (Ladle Analysis)	0.25% (for Grade I)	0.24% (for Grade RB300)	ISO 6935-1:2019
Maximum Sulphur (S) Content	0.055%	0.050%	ISO 6935-1:2019
Maximum Phosphorus (P) Content	0.055%	0.050%	ISO 6935-1:2019
Bend Test Mandrel Diameter (for bar Ø ≤ 20mm)	2d (where d = nominal diameter)	3d (for Grade 40 [280], bar Ø ≤ 16mm)	ASTM A615/A615M-22

⚠ Verify details from original standards before use

Key Values6

Quick Reference Values

yield stress mild steel grade 1250 N/mm² (up to 20mm dia)

yield stress mild steel grade 2225 N/mm² (up to 20mm dia)

yield stress medium tensile steel350 N/mm² (up to 16mm dia)

mass tolerance upto 10mm±7%

mass tolerance 10mm to 16mm±5%

mass tolerance over 16mm±3%

Tables & Referenced Sections

Key Tables

Table 1 - Chemical Composition

Table 2 - Mechanical Properties

Table 3 - Nominal Cross-Sectional Area and Mass

Key Clauses

Clause 4 - Chemical Composition

Clause 6 - Tensile Test

Clause 7 - Bend Test

Clause 9 - Tolerances on Dimensions and Nominal Mass

Frequently Asked Questions3

What is the yield strength of Mild Steel Grade I?+

250 N/mm² for bars up to 20mm diameter, as per Table 2.

Is IS 432 used for modern TMT bars?+

No, High Strength Deformed (HYSD) and TMT bars are covered under IS 1786. IS 432 is strictly for plain mild steel and medium tensile bars.

What is the standard tolerance on weight for a 12mm mild steel bar?+

±5% for bars over 10mm up to 16mm diameter, specified in Clause 9.

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IS 432 Part 1 : 1982Mild Steel and Medium Tensile Steel Bars and Hard-Drawn Steel Wire for Concrete Reinforcement - Part 1: Mild Steel and Medium Tensile Steel Bars

PDF Google Compare BIS Portal

Link points to Internet Archive / others. Not hosted by InfraLens. Details

ASTM A615/A615M · ISO 6935-1 · AS/NZS 4671

CurrentRareSpecificationStructural Engineering · Steel and Reinforcement

PDF Google Compare BIS Portal

Link points to Internet Archive / others. Not hosted by InfraLens. Details

Specifies requirements for mild steel and medium tensile steel bars used as reinforcement in concrete, commonly superseded by IS 1786 for new designs.

Quick Reference — IS 432 Part 1:1982 Plain Bar Properties

Grade I (Fe250) and Grade II (Fe350) plain mild-steel and medium-tensile bars — yield, UTS, elongation, bend, mass tolerance and chemistry.

✓ Verified 2026-04-26

Reference	Value	Clause
Grade I (mild steel) — yield stress (min)	250 MPa (≤20 mm) / 240 MPa (>20–50 mm)	Cl. 5 (Table 1)
Grade II (medium tensile) — yield stress (min)	350 MPa (≤20 mm) / 340 MPa (>20–50 mm)	Cl. 5 (Table 1)
Grade I — ultimate tensile strength (min)	410 MPa	Cl. 5 (Table 1)
Grade II — ultimate tensile strength (min)	540 MPa	Cl. 5 (Table 1)
Grade I — elongation (min, gauge 5.65√A)	23 %	Cl. 5 (Table 1)
Grade II — elongation (min)	20 %	Cl. 5 (Table 1)
Bend test — Grade I bars ≤25 mm	180° around 2 φ mandrel	Cl. 6 (Table 2)
Bend test — Grade I bars >25 mm	180° around 3 φ mandrel	Cl. 6 (Table 2)
Bend test — Grade II bars ≤25 mm	180° around 3 φ mandrel	Cl. 6 (Table 2)
Bend test — Grade II bars >25 mm	180° around 4 φ mandrel	Cl. 6 (Table 2)
Standard nominal sizes — plain round bars	6, 8, 10, 12, 16, 20, 22, 25, 28, 32, 36, 40, 45, 50 mm	Cl. 4 (Table 3)
Mass tolerance — bars 6–10 mm	± 7 % per length	Cl. 7
Mass tolerance — bars 12–16 mm	± 5 %	Cl. 7
Mass tolerance — bars ≥20 mm	± 3.5 %	Cl. 7
Carbon (max) — Grade I	0.23 %	Cl. 4 (Table 1)
Sulphur + Phosphorus (max) — Grade I	0.055 % each (S ≤ 0.055, P ≤ 0.055)	Cl. 4 (Table 1)
Carbon (max) — Grade II	0.25 %	Cl. 4 (Table 1)
Length tolerance — exact-length bars	± 25 mm (typical) / +75, −25 over 12 m	Cl. 8
Standard length — bars supplied	5–13 m (typically 12 m)	Cl. 8
Application — RCC use status	Largely superseded by IS 1786 HYSD/TMT for RCC	see IS 456 Cl. 5.6

⚠ Plain bars are now used mainly for stirrups/ties and ancillary work. RCC main reinforcement uses IS 1786. Verify against latest BIS amendments.

Overview

Status: Current
Usage level: Rare
Domain: Structural Engineering — Steel and Reinforcement
Type: Specification

International equivalents

Typically used with

IS 226 IS 228 IS 1599 IS 1608 IS 2062

Also on InfraLens for IS 432

6Key values 3Tables 3FAQs

Practical Notes

! Engineers must check the rolling tolerances on mass per meter during site material testing, as negative mass deviations beyond the permissible limit compromise the cross-sectional area.

Frequently referenced clauses

Cl. 4Chemical Composition Cl. 6Tensile Test Cl. 7Bend Test Cl. 9Tolerances on Dimensions and Nominal Mass

mild steelmedium tensile steelreinforcementFe 250

International Equivalents

Similar International Standards

ASTM A615/A615M-22ASTM International, United States

HighCurrent

Standard Specification for Deformed and Plain Carbon-Steel Bars for Concrete Reinforcement

Covers plain carbon-steel bars (Grade 40 [280]) with mechanical properties similar to IS 432's Grade I (Fe 250).

ISO 6935-1:2019International Organization for Standardization, International

HighCurrent

Steel for the reinforcement of concrete — Part 1: Plain bars

Specifically addresses plain reinforcing bars, with grade RB300 being a close functional match to the grades in IS 432.

AS/NZS 4671:2019Standards Australia / Standards New Zealand, Australia/New Zealand

HighCurrent

Steel for the reinforcement of concrete

Includes Class L plain round bars (Grade R250N) with a specified yield strength of 250 MPa, directly matching IS 432 Grade I.

BS 4449:1997BSI, United Kingdom

HighWithdrawn

Specification for carbon steel bars for the reinforcement of concrete

This historical standard included a Grade 250 for plain round bars, which was a direct equivalent to IS 432's Grade I.

Key Differences

Key Similarities

≈All standards mandate fundamental mechanical testing, including a tensile test to determine yield strength, ultimate tensile strength, and elongation, as a primary means of quality control.

≈All compared standards specify permissible manufacturing tolerances on the nominal mass per metre or nominal diameter of the bars to ensure consistency in construction.

Parameter Comparison

Parameter	IS Value	International	Source
Minimum Yield Strength (Mild Steel Grade)	250 MPa (for Grade I / Fe 250)	250 MPa (for Grade R250N)	AS/NZS 4671:2019
Minimum Ultimate Tensile Strength (UTS)	410 MPa (for Grade I / Fe 250)	420 MPa (for Grade 40 [280])	ASTM A615/A615M-22
Minimum Elongation (on 5.65√A gauge length)	23% (for Grade I / Fe 250)	22% (for Grade RB300)	ISO 6935-1:2019
Maximum Carbon (C) Content (Ladle Analysis)	0.25% (for Grade I)	0.24% (for Grade RB300)	ISO 6935-1:2019
Maximum Sulphur (S) Content	0.055%	0.050%	ISO 6935-1:2019
Maximum Phosphorus (P) Content	0.055%	0.050%	ISO 6935-1:2019
Bend Test Mandrel Diameter (for bar Ø ≤ 20mm)	2d (where d = nominal diameter)	3d (for Grade 40 [280], bar Ø ≤ 16mm)	ASTM A615/A615M-22

⚠ Verify details from original standards before use

Key Values6

Quick Reference Values

yield stress mild steel grade 1250 N/mm² (up to 20mm dia)

yield stress mild steel grade 2225 N/mm² (up to 20mm dia)

yield stress medium tensile steel350 N/mm² (up to 16mm dia)

mass tolerance upto 10mm±7%

mass tolerance 10mm to 16mm±5%

mass tolerance over 16mm±3%

Tables & Referenced Sections

Key Tables

Table 1 - Chemical Composition

Table 2 - Mechanical Properties

Table 3 - Nominal Cross-Sectional Area and Mass

Key Clauses

Clause 4 - Chemical Composition

Clause 6 - Tensile Test

Clause 7 - Bend Test

Clause 9 - Tolerances on Dimensions and Nominal Mass

Frequently Asked Questions3

What is the yield strength of Mild Steel Grade I?+

250 N/mm² for bars up to 20mm diameter, as per Table 2.

Is IS 432 used for modern TMT bars?+

No, High Strength Deformed (HYSD) and TMT bars are covered under IS 1786. IS 432 is strictly for plain mild steel and medium tensile bars.

What is the standard tolerance on weight for a 12mm mild steel bar?+

±5% for bars over 10mm up to 16mm diameter, specified in Clause 9.

QA/QC Inspection Templates

📋

QA/QC templates coming soon for this code.

Browse all 300 templates →

IS 432 Part 1 : 1982Mild Steel and Medium Tensile Steel Bars and Hard-Drawn Steel Wire for Concrete Reinforcement - Part 1: Mild Steel and Medium Tensile Steel Bars

Quick Reference — IS 432 Part 1:1982 Plain Bar Properties

Overview

International Equivalents

Key Values6

Tables & Referenced Sections

Related Resources on InfraLens

Frequently Asked Questions3

QA/QC Inspection Templates

IS 432 Part 1 : 1982Mild Steel and Medium Tensile Steel Bars and Hard-Drawn Steel Wire for Concrete Reinforcement - Part 1: Mild Steel and Medium Tensile Steel Bars

Quick Reference — IS 432 Part 1:1982 Plain Bar Properties

Overview

International Equivalents

Key Values6

Tables & Referenced Sections

Related Resources on InfraLens

Frequently Asked Questions3

QA/QC Inspection Templates