{"id":3631,"date":"2026-09-16T11:11:01","date_gmt":"2026-09-16T08:11:01","guid":{"rendered":"https:\/\/www.defencemetal.com\/index.php\/en\/aisi-434\/"},"modified":"2026-09-25T21:15:02","modified_gmt":"2026-09-25T18:15:02","slug":"aisi-434","status":"publish","type":"page","link":"https:\/\/www.defencemetal.com\/index.php\/en\/aisi-434\/","title":{"rendered":"AISI 434 \/ (1.4113)"},"content":{"rendered":"

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AISI 434 \/ (1.4113)<\/h1>\n
DEFENCE METAL<\/span><\/p>\n
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AISI 434<\/div>\n
UNS S43400 \u00b7 W.Nr. 1.4113 \u00b7 X6CrMo17-1 \u00b7 ~17% Cr – ~1% Mo. This is a FERRITIC stainless steel: the Rodacciai sheet is headed ‘FERRITIC 434’ and Ulbrich states that it ‘cannot be hardened through heat treatment’. It does NOT precipitation harden; there is NO H900 \/ H1025 type ageing step. ASTM S43400 (SSINA, BSSA, Ulbrich): C 0.12% max – Mn 1.00% max – Si 1.00% max – P 0.040% max – S 0.030% max – Cr 16.0-18.0% – Mo 0.75-1.25% – balance Fe. EN 10088 for 1.4113 (Rodacciai, worldstainless, BSSA): C 0.08% max – Si 1.00% max – Mn 1.00% max – P 0.040% max – S 0.030% max (EN 10088-3 long products, Rodacciai) or 0.015% max (EN 10088-2 flat products, worldstainless) – Cr 16.0-18.0% – Mo 0.90-1.40% – balance Fe. THE TWO STANDARDS ARE NOT THE SAME: the molybdenum band is 0.75-1.25% in ASTM and 0.90-1.40% in EN, and the carbon ceiling is 0.12% in ASTM and 0.08% in EN. THE CHROMIUM BAND IS THE SAME AS 430; molybdenum is the only thing that separates the two grades.<\/p>\n
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Not to be confused with<\/div>\n

AISI 430<\/a><\/div>\n<\/div>\n<\/div>\n

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For what<\/div>\n
Bought where 430 is not enough and molybdenum is needed. Ulbrich lists automotive trim, furnace combustion chambers, dishwashers and restaurant equipment, and states that the molybdenum addition ‘enhances corrosion resistance and resistance to deicing chemicals’;<\/div>\n<\/div>\n
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Forms<\/div>\n
Round bar, flat bar, plate, sheet, pipe, forging. All forms are supplied to order.<\/div>\n<\/div>\n
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Standards<\/div>\n
AMS: NONE. The AMS column of the Type 434 (S43400) row in the SSINA type\/specification table is EMPTY. ASTM: A240 \/ A240M (plate, sheet, strip) – it is the ONLY ASTM number on the SSINA Type 434 row. EN: 1.4113 \u00b7 EN 10088-2 (flat products) \u00b7 EN 10088-3 (long products). SAE type number: 51434.
THE SPECIFICATION COVERAGE OF 434 IS NARROW. On the Type 434 row of the SSINA type\/specification table there is only ASTM A240; the ASME, AMS, military and ACI columns are EMPTY.<\/span><\/div>\n<\/div>\n
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Advantage<\/div>\n
It carries a molybdenum floor at the same chromium level as 430. ASTM requires at least 0.75% and EN at least 0.90% molybdenum (SSINA, BSSA, Ulbrich, Rodacciai, worldstainless); 430 has no molybdenum requirement.<\/div>\n<\/div>\n
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Welding<\/div>\n
The general welding rules for ferritics apply. The SSINA welding handbook states that austenitic filler metal is used for Type 434 and recommends low-carbon austenitic wire (for example 316L) for stabilised grades;<\/div>\n<\/div>\n
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Limits<\/div>\n
1) IT DOES NOT HARDEN BY HEAT TREATMENT (Ulbrich). It gains no strength from quenching and it does not precipitation harden. 2) THE SPECIFICATION COVERAGE IS NARROW: the SSINA table carries only ASTM A240 for Type 434. No ASTM specification dedicated to 434 could be verified for bar, pipe, forgings or fasteners;<\/div>\n<\/div>\n
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Compiled from manufacturer data sheets \u00b7 confirm against the current specification before ordering<\/div>\n<\/div>\n<\/div>\n

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