OrangeSea
CNC & Precision Engineering

Materials Guide

We Machine Almost Anything

Metals, engineering plastics, and exotic superalloys — if it can be machined to tight tolerances, we have the programmes, tooling, and experience to do it. Use this guide to choose the right material for your application.

How to Choose the Right Material

Four questions to ask before specifying your material.

1

What loads will the part see?

Static loads → 6061 often sufficient. Dynamic/impact → 7075 or steel. Extreme loads at high temp → Inconel or titanium.

2

What is the operating environment?

Dry indoor use → mild steel fine. Seawater exposure → 316L or titanium. Medical/food contact → 316L, titanium, or PEEK.

3

How much does weight matter?

Weight-critical → aluminium or titanium. Weight not critical → steel is cheaper and stronger. Ultra-light → PEEK or CFRP.

4

What finishing is required?

Anodising → aluminium only. Passivation → stainless. Paint/powder coat → steel. No finish needed → stainless or PEEK.

Full Materials List

Machinability & Specifications

Machinability rating: ●●●●● = easiest (fastest, cheapest per piece). ● = hardest (specialised tooling, slower, higher cost).

Aluminium

Aluminium 6061-T6

Tensile Strength
310 MPa
Density
2.70 g/cm³
LightweightExcellent machinabilityAnodisableWeldable

The go-to alloy for most general CNC applications. Excellent strength-to-weight ratio, good corrosion resistance, and takes anodising beautifully. Easy to machine at high speeds with excellent surface finish.

Common uses: Electronics enclosures, aerospace brackets, automotive parts, bicycle components, heat sinks

Aluminium 7075-T6

Tensile Strength
570 MPa
Density
2.81 g/cm³
High strengthAerospace gradeLow weightHard anodisable

The strongest common aluminium alloy. Used wherever 6061 isn't strong enough. Slightly harder to machine than 6061 but still excellent. Cannot be welded easily — typically fastened or bonded.

Common uses: Aerospace structural parts, high-performance brackets, UAV frames, tooling fixtures

Stainless Steel

Stainless Steel 304

Tensile Strength
515 MPa
Density
7.93 g/cm³
Corrosion resistantFood safeNon-magnetic (annealed)Weldable

The most widely used stainless grade. Good corrosion resistance in most environments except chloride-rich (seawater). Work-hardens during cutting — requires sharp tooling and correct feeds/speeds.

Common uses: Food processing equipment, kitchen hardware, architectural components, chemical handling parts

Stainless Steel 316L

Tensile Strength
485 MPa
Density
7.99 g/cm³
Marine gradeBiocompatibleChloride resistantLow carbon

The addition of molybdenum gives 316L superior chloride corrosion resistance over 304. The 'L' grade (low carbon) prevents carbide precipitation during welding. Standard choice for medical and marine applications.

Common uses: Marine fittings, surgical instruments, chemical processing, pharmaceutical equipment

Titanium

Titanium Grade 5 (Ti-6Al-4V)

Tensile Strength
950 MPa
Density
4.43 g/cm³
High strength-to-weightBiocompatibleCorrosion proofNon-magnetic

The most-used titanium alloy. Excellent specific strength, fully biocompatible (ASTM F136 implant grade available), and immune to salt water corrosion. Difficult to machine — requires specialised tooling, slow speeds, heavy coolant, and careful fixturing. Our programmes are proven.

Common uses: Aerospace structures, orthopaedic implants, high-performance motorsport, marine components

Nickel Superalloy

Inconel 718

Tensile Strength
1,275 MPa
Density
8.19 g/cm³
High temp capableCreep resistantOxidation resistantAerospace spec

One of the most difficult materials to machine — work-hardens aggressively, generates extreme cutting heat, and wears tooling rapidly. We machine Inconel daily with proven feeds, speeds, and tooling strategies. Don't attempt this on a standard CNC centre without experience.

Common uses: Gas turbine components, jet engine parts, downhole oil tools, nuclear reactor hardware

Steel

Mild Steel (1018 / 1045)

Tensile Strength
400–620 MPa
Density
7.85 g/cm³
Cost-effectiveWeldableHeat treatableHigh availability

The workhorse of the engineering world. Cheap, machines cleanly, welds and heat-treats well. No inherent corrosion resistance — typically painted, powder-coated, or zinc-plated after machining. 1018 is better for cold-working; 1045 gives higher strength.

Common uses: Structural brackets, machine bases, conveyor parts, fixturing, general engineering components

Tool Steel D2 / H13

Tensile Strength
1,500–1,900 MPa (HRC 58-62)
Density
7.70 g/cm³
Extreme hardnessWear resistantDimensionally stableHeat treatable

D2 is a high-chrome cold-work tool steel used for press tooling and dies. H13 is a hot-work grade used for die casting dies and injection moulds. Both are typically rough-machined in soft state, then hardened and finish-ground to final dimensions.

Common uses: Press tooling, blanking dies, injection mould inserts, wear-resistant fixtures, cutting tools

Copper Alloy

Brass (C360 / Naval)

Tensile Strength
345–415 MPa
Density
8.50 g/cm³
Excellent machinabilityDecorativeLow frictionCorrosion resistant

C360 (free-machining brass) has the highest machinability rating of any common metal — machines at very high speeds with excellent surface finish and minimal tool wear. Naval brass adds tin for improved seawater corrosion resistance.

Common uses: Valve bodies, fittings, electrical connectors, decorative hardware, marine fittings

Copper (C110)

Tensile Strength
220 MPa
Density
8.94 g/cm³
Max conductivityThermal conductorSoftCorrosion resistant

Chosen for its electrical and thermal conductivity — both the highest of any commonly machined metal. Machines well but is soft and can smear at excessive speeds. Used wherever conductivity matters more than strength.

Common uses: Electrical busbars, heat exchanger components, RF grounding, waveguide parts

Engineering Plastic

PEEK

Tensile Strength
100 MPa
Density
1.32 g/cm³
High temp plasticBiocompatibleChemical resistantLow weight

The top-tier engineering thermoplastic. Retains mechanical properties to 250°C, fully biocompatible (USP Class VI), resistant to almost all chemicals, and X-ray transparent. Machined with sharp carbide tooling — it generates fine chips that require thorough cleaning.

Common uses: Medical device parts, aerospace interior components, chemical handling, semiconductor fixtures

Acetal (Delrin / POM-C)

Tensile Strength
70 MPa
Density
1.41 g/cm³
Low frictionDimensionally stableFood safeEasy to machine

The first choice for low-friction sliding applications. Machines with exceptional precision and surface finish — it holds tight tolerances better than most metals due to its dimensional stability. Natural white colour or black available.

Common uses: Gears, bushings, sliding components, food handling equipment, precision spacers

Not Sure Which Material to Choose?

Send us your drawing and application requirements. Our engineers review every quote submission for DFM (Design for Manufacturability) and will recommend the most cost-effective material and process.