📍 Byron House, 4 Willow Drive, Sherwood Park, Annesley, NG15 0DP
Mon–Fri 08:00–17:00 📞 01623 687 660 ✉ sales@parksidesteel.uk.com
Industry Grade Guide

Engineering Steel for Automotive
& Motorsport.

Automotive applications demand high strength-to-weight ratio, fatigue resistance and consistent heat treatment response. Sub-contract machinists serving OEM and Tier 1 suppliers encounter demanding specifications — often with recognised international grade equivalents. The industry's global nature means BS designations (EN19, EN24T, 8620) are frequently specified alongside their AISI/SAE and DIN equivalents (4140, 4340, SAE 8620, 42CrMo4).

► Request a Quote All Industries Grade Equivalents
🏎️
Sector Overview

What Automotive Manufacturing Demands from Steel Bar

Automotive steel grades are defined by their performance in three critical areas: fatigue life under cyclic loading in drivetrain and suspension; impact resistance under shock loads in gearing and transmission; and dimensional stability after heat treatment for precision gears and shafts.

The global automotive supply chain recognises a relatively small set of key grades by multiple names — 42CrMo4 / 4140 / EN19 / SCM440 are all the same steel, specified differently by different engineers from different countries working on the same vehicle programme. Parkside Steel stocks the grade to BS specification and can supply with the international equivalent noted on the mill certificate.

Key Grades

At a Glance.

EN1AFree-cutting — wheel nuts, small fittings, high-volume turnedEN1A PbLeaded free-cutting — automatic screw machinesEN8Medium carbon — stub axles, caliper componentsEN19Cr-Mo alloy — transmission shafts, driveline global standardEN24TNi-Cr-Mo Q+T — large-section shafts, performance drivetrain

Full grade list below ↓

Drivetrain Shafts & Transmission Components

EN19 (708M40 / 42CrMo4 / AISI 4140) is the global standard for automotive transmission shafts. Its Cr-Mo chemistry delivers high tensile strength (900–1100 N/mm² in the T condition), good fatigue resistance and consistent hardenability to approximately 65mm section. Recognised worldwide as 42CrMo4 / SCM440 / 4140, it is specified on automotive drawings from Europe, North America and Japan.

For heavily stressed or large-section drivetrain components — output shafts, crown wheel and pinion, differential casings — EN24T (817M40T / 34CrNiMo6 / AISI 4340) adds nickel for superior deep-section hardenability and impact toughness. The T suffix indicates supply in the quenched and tempered condition — machined directly to drawing without further heat treatment.

Recommended Grades
EN19 (708M40 / 42CrMo4) Global drivetrain standard. High tensile, Cr-Mo. 900–1100 N/mm² in T condition. EN24T (817M40T / 4340) Ni-Cr-Mo. Deep-section hardening. Pre-treated — machine direct to drawing. EN16 (605M36 / 34CrMo4) Cr-Mo. Between EN8 and EN19 in hardenability. Medium-duty drivetrain.

Gears, Camshafts & Case Hardened Components

SAE 8620 (805M20 / 20NiCrMo2) is the most widely used case hardening steel in the global automotive supply chain — specified by name on countless gearbox and differential gear drawings from every major OEM. It provides a reliable combination of case hardness (58–62 HRC) and core toughness after carburising, at a cost well below the premium grades.

For performance and motorsport applications where shock loading is severe, EN36 (655M13 / 14NiCr14) delivers superior core impact resistance — the high nickel content (3.0–3.75% Ni) maintains core toughness that SAE 8620 cannot match under impact.

Recommended Grades
8620 (805M20 / SAE 8620) Automotive gear standard. 58–62 HRC case. Consistent carburising response. EN36 (655M13 / 14NiCr14) Premium case hardening. Superior core toughness. Motorsport and heavy-duty gearing.

Fasteners, Wheel Nuts & High-Volume Turned Parts

High-volume automotive fastener and turned component production runs on automatic lathes — and automatic lathe production runs on EN1A (230M07 / 11SMn30). Wheel nuts, inserts, small hydraulic fittings and any high-volume CNC turned component benefit from the free-cutting properties that give consistent chip-breaking, extended tool life and clean surface finish.

EN1A Pb (230M07Pb) is used where maximum cutting speed is needed on automatic screw machines producing small, intricate parts. Both grades are widely stocked in hexagon bar form for direct nut production without preliminary turning to a hex profile.

Recommended Grades
EN1A (230M07) Free-cutting. Wheel nuts, inserts, small fittings. Extended tool life. EN1A Pb (230M07Pb) Leaded. Maximum cutting speed on automatic screw machines. EN8 (080M40) Medium carbon. Stub axles, caliper parts, components needing strength.
All Grades for Automotive & Motorsport

Recommended Grades — Full List.

Click any grade for full data sheet, chemical composition, mechanical properties and heat treatment guidance.

EN1A 230M07 Free-cutting — wheel nuts, small fittings, high-volume turned EN1A Pb 230M07Pb Leaded free-cutting — automatic screw machines EN8 080M40 Medium carbon — stub axles, caliper components EN19 42CrMo4 Cr-Mo alloy — transmission shafts, driveline global standard EN24T 817M40T Ni-Cr-Mo Q+T — large-section shafts, performance drivetrain 8620 SAE 8620 Automotive case hardening standard — gears, camshafts EN36 655M13 Premium case hardening — motorsport and heavy duty gearing EN36C 832M13 Ni-Cr-Mo case hardening — large section, premium motorsport

Not sure which grade is right? Call our sales team on 01623 687 660 — we can advise based on your component, loading and heat treatment requirements.

Common Questions

Frequently Asked.

EN19 (708M40) is the closest UK equivalent to AISI 4140 and DIN 42CrMo4. The chemical compositions are very similar — both are chromium-molybdenum steels with approximately 0.40% C, 1.0% Cr and 0.20% Mo. Mill certificates can be dual-certified to both standards on request.
SAE 8620 is equivalent to BS 805M20 and BS EN 20NiCrMo2-2. Parkside Steel stocks 805M20 which dual certifies to SAE 8620 — the most commonly used automotive case hardening steel worldwide.
Yes. EN 10204 3.1 material test certificates are available on all alloy grades including EN19, EN24T, 8620 and EN36. Request when ordering — certificates accompany the delivery or are supplied electronically.
Explore Further

Related Industries.

Defence & Aerospace ► General Engineering ► MRO & Maintenance ►
Colour-coded bright bar ends — yellow and purple grade identification for automotive grades
Small diameter bright bar ends in pigeonhole racking — multiple grades for automotive production

Talk to Us About Your Automotive & Motorsport Requirements.

3.1 certs available — global grade equivalents — cut to length. Our sales team understands engineering steel — not just the catalogue. Call with a grade, a component description, or a question.

📞
01623 687 660Mon–Fri 08:00–17:00 — speak to sales direct
 📋
Request a QuoteGrade, size, quantity and cert requirement
 📚
Technical LibraryGrade data sheets, equivalents, tolerances