Bought where more hardness and wear resistance are needed than 420 gives, but the brittleness of 420C is not wanted: cutting edges and blades, surgical and dental instruments, valve and pump parts, bearings, shafts, die and gauge parts, plastic injection moulds, measuring tools.<\/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
EN: 1.4028 \u00b7 10088-2 (flat products; +A and +QT800) \u00b7 10088-3 (bars; +A and +QT850) \u00b7 10250-4 (open die forgings) \u00b7 EN ISO 7153-1:2016 (surgical instruments, 1.4028 \/ X30Cr13). ASTM: F899 (surgical instruments; 420B = C 0.26-0.35%, Cr 12.00-14.00%, Ni 1.00% max, UNS S42000) \u00b7 A276 \/ SA-276 (bars and shapes; carried in the standard as ‘Type 420’, Condition A only, with a hardness ceiling) \u00b7 A314 \/ SA-314 (billets and bars for forging) \u00b7 A484 \/ SA-484 (general requirements) \u00b7 A580 \/ SA-580 (wire). The Stainless Fruechtl document also lists NF S 94-090. Welding wire: AWS A5.9 \/ SFA-5.9 ER420. AMS: there is NO AMS number specific to 1.4028; the 0.30-0.40% band of
AMS 5506<\/b> and 5621 overlaps this grade’s band only PARTLY – see the specification note.
THE AMS OVERLAP – THIS IS THE SITUATION SPECIFIC TO 420B. Verified from SAE title records: AMS 5506 and AMS 5621 carry the band ’13Cr (0.30 – 0.40C)’. The band of 1.4028 is 0.26-0.35%. THE TWO BANDS OVERLAP ONLY BETWEEN 0.30 AND 0.35%.<\/span><\/div>\n<\/div>\n\n
Advantage<\/div>\n
It sits in the middle of the carbon ladder, and the numbers for that come from one table in one Notz document: tempered at 200-350 \u00b0C, 1.4021 gives 44-50 HRC and 1400-1700 N\/mm\u00b2, 1.4028 gives 45-51 HRC and 1430-1730 N\/mm\u00b2. Same document, same tempering band, carbon the only variable.<\/div>\n<\/div>\n
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Welding<\/div>\n
420B is NOT a material chosen for welding. Where welding is unavoidable, the martensitic stainless cycle is applied: PREHEAT at least 200 \u00b0C; the band Hobart gives as commonly specified for martensitic stainless steels is 204-316 \u00b0C (400-600 \u00b0F);<\/div>\n<\/div>\n
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Limits<\/div>\n
1) FORBIDDEN TEMPERING BAND: 400-600 \u00b0C. Stainless Fruechtl states it directly for 1.4028: harden from 980 \u00b0C, temper from 200 \u00b0C, AVOIDING the 400-600 \u00b0C zone. For the same family, Swiss Steel gives 400-600 \u00b0C (1.4021), Abrams gives 425-600 \u00b0C (1.4034), and AZoM and Atlas give 425-600 \u00b0C (420).<\/div>\n<\/div>\n