{"id":3557,"date":"2026-09-16T11:00:01","date_gmt":"2026-09-16T08:00:01","guid":{"rendered":"https:\/\/www.defencemetal.com\/index.php\/en\/h11\/"},"modified":"2026-09-25T16:30:43","modified_gmt":"2026-09-25T13:30:43","slug":"h11","status":"publish","type":"page","link":"https:\/\/www.defencemetal.com\/index.php\/en\/h11\/","title":{"rendered":"H11"},"content":{"rendered":"

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H11 \/ AMS 6487 \/ AMS 6437<\/h1>\n
DEFENCE METAL<\/span><\/p>\n
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H11<\/div>\n
UNS T20811 \u00b7 W.Nr. 1.2343 \u00b7 EN ISO 4957 X37CrMoV5-1 (former DIN name X38CrMoV5-1) \u00b7 JIS SKD6 \u00b7 BS BH11 \u00b7 ~5% Cr – 1.3% Mo – 0.4% V – C ~0.37%. THIS IS A 5% CHROMIUM HOT WORK TOOL STEEL. EN ISO 4957 band (1.2343): C 0.33-0.41% – Si 0.80-1.20% – Mn 0.25-0.50% – Cr 4.80-5.50% – Mo 1.10-1.50% – V 0.30-0.50% – P 0.030% max – S 0.020% max. The ASTM A681 \/ AISI H11 band is NOT THE SAME: C 0.33-0.43% – Mn 0.20-0.50\/0.60% – Si 0.80-1.20\/1.25% – Cr 4.75-5.50% – Mo 1.10-1.60% – V 0.30-0.60%. The two bands do not overlap at the carbon ceiling (EN 0.41%, ASTM 0.43%) or the vanadium ceiling (EN 0.50%, ASTM 0.60%); material certified to 1.2343 is therefore not automatically acceptable against an ASTM A681 H11 order. AEROSPACE H-11 (AMS 6487 \/ 6437) IS A THIRD BAND: C 0.38-0.43%, nominally 5.0Cr – 1.3Mo – 0.50V; AMS 6487 additionally requires CONSUMABLE ELECTRODE VACUUM RE-MELTING (CEVM\/VAR). IT IS NOT STAINLESS. It does NOT precipitation harden; there is NO ageing step of the H900 \/ H1025 \/ H1150 type. The hardening route is: austenitise – harden in air, oil or a salt bath – DOUBLE (preferably TRIPLE) TEMPER. The tempering curve shows SECONDARY HARDENING: hardness rises again around 450-510 \u00b0C.<\/div>\n
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Not to be confused with<\/div>\n

AISI 4140<\/a><\/div>\n<\/div>\n

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For what<\/div>\n
It is bought for two distinct jobs, and one material quality does not serve both. (1) HOT WORK TOOLING: die casting dies, forging dies, extrusion tooling (liners, stems, container mantles, pressure pads, mandrels, die holders), hot shear blades, hot punches and plastic injection moulds – work in\u2026<\/div>\n<\/div>\n
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Forms<\/div>\n
Round bar \u00b7 flat bar \u00b7 plate \u00b7 sheet \u00b7 pipe\/tube \u00b7 forgings. All forms are supplied to order. NOTE: AMS coverage splits by form – AMS 6487 covers bars, forgings and forging stock only, AMS 6437 covers sheet, strip and plate only, and no verified H-11 AMS number was found for tube (see the standards map).<\/div>\n<\/div>\n
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Standards<\/div>\n
AMS (ACTIVE, verified one by one): 6487 – ‘Steel, Bars, Forgings, and Forging Stock 5.0Cr – 1.3Mo – 0.50V (0.38 – 0.43C) (H-11) Consumable Electrode Vacuum Re-Melted’, premium aircraft quality, current revision M\/2021 (revision N is work in progress at SAE) \u00b7 6437 – ‘Steel, Sheet, Strip, and Plate, 5.0Cr – 1.3Mo – 0.50V (0.38 – 0.43C) (H-11), Aircraft Quality’, current revision L\/2025 (previous K\/2020). AMS (CANCELLED – NOT TO BE PUT ON AN ORDER): 6485H\/1989 ‘Steel Bars and Forgings, 5.0Cr 1.3Mo 0.50V (0.38-0.43C)’ – CANCELLED October 2006, superseded by AMS 6487<\/b> \u00b7 6488H ‘Steel, Bars and Forgings 5.0Cr 1.3Mo 0.50V (0.38-0.43C)’ (premium quality) – CANCELLED January 2008; the ANSI record carries the note that ‘similar but not necessarily identical products are covered in AMS 6487<\/b>‘. ASTM: A681 – ‘Standard Specification for Tool Steels Alloy’; its scope covers hot or cold finished bar, plate, sheet, strip, rod, wire and forgings. EN \/ ISO: EN ISO 4957:2018 ‘Tool steels’ (ISO 4957:2018, 3rd edition, 2018-06) – 1.2343 \/ X37CrMoV5-1. OTHER NATIONAL: JIS G4404 SKD6 \u00b7 BS 4659 BH11. INDUSTRY: NADCA #207 acceptance and heat treat criteria (the B\u00d6HLER W300 ISOBLOC page carries the NADCA D1830 \/ #207 designation).
TOOL STEEL H11 AND AEROSPACE H-11 ARE NOT THE SAME THING. The difference sits at three points:
\n1) CARBON BAND. The ASTM A681 H11 band is C 0.33-0.43%; the band in the AMS 6487 and AMS 6437 titles is C 0.38-0.43%.<\/span><\/div>\n<\/div>\n
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Advantage<\/div>\n
Its single most important practical advantage is SECONDARY HARDENING: as the tempering temperature rises, hardness first falls and then RISES AGAIN. The curve Lucefin measured on a specimen oil quenched from 1020 \u00b0C is: 52 HRC at 250 \u00b0C, 53.5 HRC at 350 \u00b0C, 55.5 HRC at 450 \u00b0C and 56 HRC at 510 \u00b0C.<\/div>\n<\/div>\n
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Welding<\/div>\n
IT IS WELDABLE, BUT A HIGH PREHEAT IS MANDATORY, and the delivery condition of the part governs the welding decision. PREHEAT: the B\u00d6HLER tool welding handbook gives 350-400 \u00b0C for the 1.2343 \/ W300 class in the soft annealed condition and 400-450 \u00b0C in the hardened condition.<\/div>\n<\/div>\n
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Limits<\/div>\n
1) IT IS NOT STAINLESS. Chromium is 4.75-5.50%, which is not enough to form a passive layer. Without oil, plating or another protective measure it rusts in damp air; it is not suitable for marine or chloride-bearing environments.<\/div>\n<\/div>\n
REQUEST A QUOTE<\/a>All alloy steels →<\/a>TECHNICAL DETAILS ↓<\/span><\/div>\n
Compiled from manufacturer data sheets \u00b7 confirm against the current specification before ordering<\/div>\n<\/div>\n<\/div>\n

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