Steel Parts Australia
Custom steel machined parts in 4140, EN24, 1045, 4340, and all standard engineering steel grades. Mining, oil and gas, heavy engineering, and defence applications. Send us your drawing — we source, manage, inspect and deliver complete finished parts.
Steel Grade Selection
Selecting the right steel grade ensures your parts meet the strength, toughness, machinability, and heat treatment requirements of your application.
| Grade | Key Properties | Best Applications |
|---|---|---|
| 1045 | Medium carbon, good machinability | General engineering, shafts, gears |
| 4140 | Chromium-molybdenum, heat treatable | Mining components, shafts, tooling, oil and gas |
| 4340 | Nickel-chromium-moly, high strength | Heavy duty shafts, gears, aerospace |
| EN8 (080M40) | UK spec medium carbon | General engineering, shafts, couplings |
| EN24 (817M40) | Nickel-chrome-moly, tough | High-load applications, mining, oil and gas |
| D2 Tool Steel | High carbon-chromium, wear resistant | Dies, punches, cutting tools, wear plates |
Industries Using Steel Machined Parts
Mining & Resources
4140 and EN24 are the workhorses of Australian mining — drive shafts, gearbox components, bearing housings, impellers, pump parts. Heat treatment to specification included.
- ✓ 4140 and EN24 common
- ✓ Heat treatment to spec
- ✓ Wear-resistant options
- ✓ Full material certs
Oil & Gas
High-pressure components in 4140, 4340, and stainless. Valve bodies, spool pieces, manifolds, and downhole components to NACE standards.
- ✓ 4140, 4340, 17-4 PH
- ✓ Pressure-rated designs
- ✓ NACE MR0175 aware
- ✓ Full traceability
Heavy Engineering
Large machined components in structural and engineering steels. Horizontal boring, large-format turning, and grinding for shafts, housings, and infrastructure components up to 10 tonnes.
- ✓ Up to 10 tonne components
- ✓ Large-format machining
- ✓ ±0.01mm tolerances
- ✓ Cylindrical grinding available
Steel Parts FAQ
What steel grades are available for machined parts in Australia?
We supply steel machined parts in all standard grades: 1018 (low carbon, good weldability, general use), 1045 (medium carbon, shafts, gears), 4140 (chromium-molybdenum alloy, heat treatable, most common engineering alloy steel in Australian mining and oil and gas), 4340 (nickel-chromium-molybdenum, highest strength — aerospace and heavy engineering), EN8 (080M40 — UK/Australian medium carbon equivalent), EN24 (817M40 — nickel-chrome-moly, tough, shock resistant), AR400/Bisalloy wear plates (abrasion resistant), D2 (high chromium cold work tool steel), H13 (hot work tool steel), and A2 (air hardening tool steel). Material certification provided with all orders.
What is 4140 steel and why is it the most common engineering alloy steel in Australia?
4140 is a chromium-molybdenum alloy steel (AISI/SAE designation: ~1% Cr, 0.2% Mo, 0.4% C). It is the most widely used alloy steel in Australian industry for several reasons: excellent machinability in annealed condition, good weldability (with preheat), heat treatable to a wide range of strength levels (typically 850–1000 MPa UTS as supplied in 'T' condition), excellent toughness and fatigue resistance, and wide availability across Australian steel distributors. Applications include shafts, gears, bolts, mining components, tooling, oil and gas fittings, and any high-load application requiring toughness and strength.
What is EN24 steel and where is it used in Australian industry?
EN24 is the British standard designation for a nickel-chromium-molybdenum alloy steel (equivalent to AISI 4340). It contains approximately 1.5% nickel, 1.2% chromium, and 0.25% molybdenum, giving it superior toughness and hardenability compared to 4140. EN24 is widely used in Australian mining equipment, oil and gas downhole tools, heavy vehicle drive components, gearbox shafts, and high-duty industrial applications where 4140 is insufficient. It machines cleanly in normalised condition, responds well to heat treatment to 850–1100 MPa, and holds tight tolerances after grinding.
Can steel parts be heat treated as part of the manufacturing process?
Yes. Heat treatment is arranged through our supplier network and included in the quote. Common processes available: stress relieving (after rough machining for large parts), normalising (refine grain structure, relieve machining stress), quench and temper (harden and temper to specified Rockwell hardness), case hardening (carburising for surface hardness with tough core — gears and shafts), induction hardening (localised surface hardening), nitriding (surface hardness without distortion), and annealing (soften for machining). Specify your required hardness or heat treatment condition on your drawing or in your quote request.
What surface treatments are available for steel machined parts?
Steel machined parts can be surface treated to improve corrosion resistance and appearance: zinc plating (electroplating — corrosion protection for general engineering), hot dip galvanising (thick zinc coating for structural applications), black oxide (decorative, mild corrosion resistance), electroless nickel plating (uniform coating including internal bores, wear and corrosion resistance), chrome plating (hard chrome for wear surfaces, decorative chrome), powder coating (polyester or epoxy — colour and corrosion protection), and phosphating (Parkerising — base for paint, mild corrosion protection). Specify required treatment on your drawing.
What tolerances can be achieved on steel machined parts?
Standard CNC machining of steel achieves ±0.05mm on general features. Precision machining holds ±0.01mm on critical dimensions. For shafts and bores requiring press fits or bearing fits, cylindrical grinding achieves ±0.005mm or better. Ground shafts with h6 tolerance (typically ±0.006–0.011mm depending on diameter) are common for bearing housings. Specify fits using ISO tolerance codes (e.g., h6 shaft, H7 bore) on your 2D drawing for the correct grinding allowance.
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