High-strength abrasion-resistant steel plate

01

Choose the hardness grade

SSAB describes its Hardox 450 plate as having a nominal hardness of 450 HBW with good bendability and weldability, 50 HBW harder than its 400 grade for better dent and abrasion resistance and longer wear life, or the option of a thinner plate for lighter equipment, with similar toughness to AR 400 steels. [1]

SSAB's welding guide says all Hardox grades resist hydrogen cracking better than other wear-resistant steels because of their relatively low carbon equivalent, gives the CEV and CET formulas, and states that alloy contents are on the mill certificate and "The typical carbon equivalent for all Hardox® grades is guaranteed in SSAB's product data sheets", and that "A higher carbon equivalent usually requires a higher preheating and interpass temperature". [2]

Editorial note: suppliers on this page list grades such as NM360 to NM550 and AR550; compare them on the guaranteed hardness range, impact toughness at temperature and carbon equivalent for the thickness you buy, not on the name.

Give the supplier the grade or hardness range, thickness, width and length, flatness, impact toughness requirement and test temperature, carbon equivalent limit, cutting and bending plans, welding processes, quantity, and mill certificate type.

02

Preheat, control hydrogen and avoid post-weld heat treatment

SSAB's preheat table for Hardox 450 plate gives no preheat up to 25.0 mm, 125 °C minimum for 25.1–40.0 mm and 150 °C minimum for 40.1–160.0 mm, with a maximum interpass temperature of 225 °C throughout; sheet of 2.0–8.0 mm needs no preheat and at most 100 °C interpass. [3]

The welding guide applies these values to tack welds and root runs, uses the thicker plate's requirement when thicknesses differ, and adds 25 °C at heat inputs of 1.0–1.69 kJ/mm or when humidity is high or the temperature is below 5 °C. It recommends consumables giving at most 5 ml of hydrogen per 100 g of weld metal, clean joints, weld starts and stops 50–100 mm from corners, root openings and gaps no more than 3 mm, and shifting the root pass about 5 mm off the plate centreline above 25 mm. [2]

SSAB says post-weld heat treatment can stress-relieve its HiTuf and HiTemp grades but should not be used on other Hardox steels because it may impair mechanical properties. [2] Editorial calculation: a 30 mm Hardox 450 plate welded at 1.2 kJ/mm would need 125 + 25 = 150 °C minimum preheat under these rules, below the 225 °C interpass limit.

03

NM360–NM550 and AR-type plate on the listed mills' pages

Listings include NM360 to NM550 and AR-type wear-resistant plates alongside carbon and structural steels.

04

Check a second mill's guaranteed values before comparing grades

voestalpine's technical terms of delivery for its durostat wear-resistant steels (January 2024) guarantee 410–490 HB as delivered for durostat 450 and apply to plate from 5 to 70 mm. Maximum carbon equivalent is CEV 0.57 and CET 0.37 up to 15 mm, and CEV 0.59 and CET 0.39 above 15 up to 70 mm. Charpy-V impact energy at −40 °C is guaranteed only on request and surcharge: 20 J minimum for 5–50 mm, against a standard value of 30 J at 20 mm. [4]

The same document gives standard values at 20 mm of 1,100 MPa yield strength, 1,400 MPa tensile strength and 9% elongation; minimum bending radii of 5 × plate thickness longitudinal and 4 × transverse; no preheat for thermal cutting up to 20 mm and at least 60 to 80 °C above that; and a ban on heating the plate above 250 °C if it is to keep its hardness. Hardness is measured per heat and every 40 t, about 1–2 mm below the surface, and the impact test and the EN 10204 certificate type must be agreed at ordering. [4]

Editorial calculation: a 20 mm durostat 450 plate needs an inside bending radius of at least 5 × 20 = 100 mm for the longitudinal value and 4 × 20 = 80 mm for the transverse value. Ask each supplier for guaranteed values, not standard values, for the thickness you buy.

05

Hardness, toughness, carbon equivalent, thickness and primer

Thickness and carbon equivalent are the rows that change the welding procedure: SSAB's Hardox 450 preheat steps up at 25 and 40 mm, and its welding guide ties preheat to carbon equivalent. [3] [2]

06

Hardness, strength, toughness, carbon equivalent and plate size for an AR plate order

SSAB's figures fill the hardness, thickness and carbon-equivalent rows. For yield, tensile and impact values, voestalpine's durostat terms above separate standard values from guaranteed ones, so ask which kind each quoted figure is. [1] [4]

07

Send the grade, size and fabrication data together

Paste it into your enquiry below or into an email to a maker, then replace every bracket.

Grade: [hardness range; toughness; CE limit]
Sizes: [thickness; width; length; flatness]
Fabrication: [cutting; bending; welding processes]
Welding: [consumables; preheat capability]
Use: [wear type; impact; temperature]
Documents: [mill certificate type]

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