Vacuum carburising, widely used outside the UK, has recently become available domestically. It offers Vacuum carburising, now available in the UK, offers distinct advantages over conventional gas carburising, making it an ideal choice for high-precision applications.

Advantages:

• Oxide-Free Surface: Reduces wear, improves fatigue resistance, and prevents micro-cracking.
• Excellent Hole Penetration: Pulsed gas pressure ensures consistent gas flow into holes, improving penetration.
• Lower Distortion: Slower quench rate results in less distortion compared to oil quenching, with even less distortion when using vacuum carburising steel.
• Superior Finish: Achieves a finish similar to vacuum hardening due to the vacuum chamber process.
• Shorter Process Time: Higher carburising temperatures and no post-treatment cleaning lead to faster cycle times.
• Improved Reliability: Delivers consistent and repeatable hardness profiles.
• No Inter-granular Oxidation (IGO): Eliminates inter-granular attack, reducing fatigue failure risk.

Disadvantages:

• Not Suitable for Low Hardenability Steels: Less effective for steels with low hardenability due to nitrogen pressure quenching limits.
• Corrosion Protection Required: Components need protection from corrosion after processing, as with other vacuum treatments.
• Masking Needed: Threaded holes can be blocked, but other areas require mechanical masking.

Applications:

• Gears: Ideal for gears that require grinding after heat treatment, as it eliminates oxide layers and reduces distortion.
• Fuel Injectors: Perfect for components needing uniform carburised layers in hard-to-reach areas.
• Complex Shapes: Suitable for parts with intricate shapes that retain oil after oil quenching.

Vacuum carburising is an advanced, efficient process offering superior finishes, reliability, and performance, especially in automotive, aerospace, and other critical industries.