---
title: "431 Stainless Steel Round Bar, 16 to 125 mm | Laxcon Steels"
source: "https://www.laxconsteels.com/products/hot-rolled-round-bars/aisi-431/"
description: "AISI 431 stainless steel hot rolled round bar, made to order by Laxcon Steels, India: composition, equivalents, weight per metre and tolerances."
---
# AISI 431 Round Bars

*[Home](https://www.laxconsteels.com/) > [Products](https://www.laxconsteels.com/products/) > [Hot Rolled Round Bars](https://www.laxconsteels.com/products/hot-rolled-round-bars/) > AISI 431*

AISI 431 hot rolled round bar is a nickel bearing martensitic stainless bar used for shafts, valve parts and marine bolting.

16 to 125 mm Martensitic stainless steel Made to order

## AISI 431 hot rolled round bar

AISI 431 hot rolled round bar is a martensitic stainless steel hot rolled to round section, in diameters from 16 to 125 mm. The grade carries 15 to 17 percent chromium with 1.25 to 2.5 percent nickel, more chromium than AISI 410 and an addition of nickel that 410 does not have. That pairing is why it is specified: it reaches a higher strength after hardening and tempering than 410, and it holds up better in damp air and mild chloride service. Against AISI 420, which carries more carbon, 431 gives up peak hardness and gains toughness and corrosion resistance, so it suits loaded parts rather than cutting edges. The grade is also written 1.4057, SUS 431 and UNS S43100. Laxcon Steels rolls the bar to order.

The bar leaves the mill black as rolled, spot ground or fully ground, in lengths up to 8 metres. It is normally supplied annealed, the soft condition in which the steel machines and drills without trouble, and it is hardened afterwards by austenitising, quenching in oil or water and tempering to the strength the finished part needs. The steel is magnetic in every condition. Welding is awkward, because the weld zone hardens as it cools, so a joint needs preheat and a temper after welding. Work in this form runs to pump and compressor shafts, valve stems and spindles, marine and oilfield bolting, and gear and coupling blanks that the customer machines or forges to shape.

Composition limits in weight percent are carbon 0.2 maximum, manganese 1.0 maximum, sulphur 0.03 maximum, phosphorus 0.04 maximum, silicon 1.0 maximum, chromium 15.0 to 17.0 and nickel 1.25 to 2.5.

## AISI 431 hot rolled round bar supply conditions

| Property | Value |
| --- | --- |
| Size range | 16 mm - 125 mm (5/8" - 5") |
| Length | Up to 8 metres |
| Tolerances | ASTM A484, EN10060 |
| Heat treatment | Soft annealing; oil or water quenching and tempering |
| Grade | AISI 431 (431, SUS 431, 1.4057, S43100) |
| Family | Martensitic stainless steel |
| Supply | Made to order in this grade; every published size of the form |

## Composition of AISI 431

| Element | Symbol | Minimum % | Maximum % |
| --- | --- | --- | --- |
| Carbon | C |  | 0.2 |
| Manganese | Mn |  | 1.0 |
| Sulphur | S |  | 0.03 |
| Phosphorus | P |  | 0.04 |
| Silicon | Si |  | 1.0 |
| Chromium | Cr | 15.0 | 17.0 |
| Nickel | Ni | 1.25 | 2.5 |

Composition, weight percent, balance iron. From the Laxcon Steels grade reference.

## Equivalents of AISI 431

| Standard | Designation |
| --- | --- |
| UNS | S43100 |
| EN number | 1.4057 (X17CrNi16-2) |
| JIS | SUS 431 |

Equivalence means nearest counterpart, not identity: each standards body sets its own composition window, so the limits of the standard named on the order govern.

## Governing standards

| Property | Value |
| --- | --- |
| EN 10088-3 | Stainless steels: technical delivery conditions for semi-finished products, bars, rods, wire, sections and bright products for general purposes. Composition, heat treatment condition and mechanical properties per grade. |
| EN 10060 | Hot rolled round steel bars for general purposes: dimensions and tolerances on shape and dimensions. |
| ASTM A276/A276M | Stainless steel bars and shapes: composition, condition, mechanical properties and finish designations for hot-finished and cold-finished bar. |
| ASTM A484/A484M | General requirements for stainless steel bars, billets and forgings: permissible variations in dimensions, straightness, weight and length, and the test and marking requirements every bar order inherits. |
| ASTM A479/A479M | Stainless steel bars and shapes for use in boilers and other pressure vessels: the bar specification a pressure-part drawing calls for. |
| ASTM A314 | Stainless steel billets and bars for forging. |
| NACE MR0175 / ISO 15156 | Materials for use in H2S-containing environments in oil and gas production: the sour-service limits on hardness and condition. |
| EN 10204 | Metallic products, types of inspection documents: the 2.2 test report and the 3.1 and 3.2 inspection certificates a purchase order can call for. |

## Weight per metre

| Diameter (mm) | kg per metre | Metres per tonne |
| --- | --- | --- |
| 16 | 1.59 | 629.5 |
| 17 | 1.79 | 557.6 |
| 18 | 2.01 | 497.4 |
| 19 | 2.24 | 446.4 |
| 20 | 2.48 | 402.9 |
| 21 | 2.74 | 365.4 |
| 22 | 3.00 | 333.0 |
| 23.2 | 3.34 | 299.4 |
| 24 | 3.57 | 279.8 |
| 25 | 3.88 | 257.9 |
| 26 | 4.19 | 238.4 |
| 27 | 4.52 | 221.1 |
| 28 | 4.86 | 205.6 |
| 30 | 5.58 | 179.1 |
| 32 | 6.35 | 157.4 |
| 34 | 7.17 | 139.4 |
| 36 | 8.04 | 124.4 |
| 37 | 8.49 | 117.7 |
| 38 | 8.96 | 111.6 |
| 40 | 9.93 | 100.7 |
| 42 | 10.95 | 91.4 |
| 45 | 12.57 | 79.6 |
| 47 | 13.71 | 73.0 |
| 48 | 14.30 | 69.9 |
| 50 | 15.51 | 64.5 |
| 53 | 17.43 | 57.4 |
| 56 | 19.46 | 51.4 |
| 57.5 | 20.52 | 48.7 |
| 60 | 22.34 | 44.8 |
| 63 | 24.63 | 40.6 |
| 66 | 27.03 | 37.0 |
| 67.5 | 28.27 | 35.4 |
| 70 | 30.40 | 32.9 |
| 73.5 | 33.52 | 29.8 |
| 75 | 34.90 | 28.7 |
| 77.5 | 37.27 | 26.8 |
| 80 | 39.71 | 25.2 |
| 83 | 42.75 | 23.4 |
| 85 | 44.83 | 22.3 |
| 88 | 48.05 | 20.8 |
| 90 | 50.26 | 19.9 |
| 93 | 53.67 | 18.6 |
| 95 | 56.00 | 17.9 |
| 98 | 59.59 | 16.8 |
| 100 | 62.05 | 16.1 |
| 105 | 68.41 | 14.6 |
| 106 | 69.72 | 14.3 |
| 110 | 75.08 | 13.3 |
| 115 | 82.06 | 12.2 |
| 120 | 89.35 | 11.2 |
| 125 | 96.95 | 10.3 |

Density 7.90 g/cm³, diameter squared x 0.006205. Sizes are the published range at the nominal diameters shown.

## Ordering AISI 431 hot rolled round bar

An enquiry for this grade states the grade and governing standard, AISI 431 to ASTM A276 or 1.4057 to EN 10088-3, the condition, annealed or hardened and tempered to an agreed strength, the diameter with the tolerance class to ASTM A484 or EN 10060, the length, the surface, black, spot ground or fully ground, the quantity, the test certificate type to EN 10204, and any ultrasonic test or PMI check required.

## Other grades in Round Bars

- [**AISI 304** The general purpose austenitic stainless steel](https://www.laxconsteels.com/products/hot-rolled-round-bars/aisi-304/)
- [**AISI 316** The molybdenum-bearing austenitic grade](https://www.laxconsteels.com/products/hot-rolled-round-bars/aisi-316/)
- [**EN 8** A medium-carbon unalloyed engineering steel](https://www.laxconsteels.com/products/hot-rolled-round-bars/en-8/)
- [**Duplex 2205** The standard duplex stainless steel](https://www.laxconsteels.com/products/hot-rolled-round-bars/duplex-2205/)
- [**SAE 4140** The chromium-molybdenum through-hardening steel](https://www.laxconsteels.com/products/hot-rolled-round-bars/sae-4140/)
- [**AISI 303** The free-machining austenitic grade](https://www.laxconsteels.com/products/hot-rolled-round-bars/aisi-303/)
- [**AISI 316L** The low-carbon version of AISI 316](https://www.laxconsteels.com/products/hot-rolled-round-bars/aisi-316l/)
- [**AISI 410** The basic martensitic stainless steel](https://www.laxconsteels.com/products/hot-rolled-round-bars/aisi-410/)
- [**SAE 4340** The nickel-chromium-molybdenum through-hardening steel](https://www.laxconsteels.com/products/hot-rolled-round-bars/sae-4340/)
- [**AISI 416** The free-machining martensitic grade](https://www.laxconsteels.com/products/hot-rolled-round-bars/aisi-416/)
- [**17-4 PH** The precipitation hardening stainless steel](https://www.laxconsteels.com/products/hot-rolled-round-bars/17-4-ph/)
- [**AISI 420** A higher-carbon martensitic stainless steel](https://www.laxconsteels.com/products/hot-rolled-round-bars/aisi-420/)
- [**AISI 304L** The low-carbon version of AISI 304](https://www.laxconsteels.com/products/hot-rolled-round-bars/aisi-304l/)
- [**AISI 430** The standard ferritic stainless steel](https://www.laxconsteels.com/products/hot-rolled-round-bars/aisi-430/)
- [**EN 24** A nickel-chromium-molybdenum engineering steel for heavy sections](https://www.laxconsteels.com/products/hot-rolled-round-bars/en-24/)
- [**Super duplex 2507** A super duplex stainless steel](https://www.laxconsteels.com/products/hot-rolled-round-bars/super-duplex-2507/)
- [**AISI 310S** A high-chromium, high-nickel austenitic grade for continuous service](https://www.laxconsteels.com/products/hot-rolled-round-bars/aisi-310s/)
- [**AISI 321** AISI 304 stabilised with titanium](https://www.laxconsteels.com/products/hot-rolled-round-bars/aisi-321/)
- [**EN 19** A chromium-molybdenum engineering steel](https://www.laxconsteels.com/products/hot-rolled-round-bars/en-19/)

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