IS09001 2015

Heat Treatment

Heat Treatment Furnace

Precision Heat Treatment Engineering at NTG

For over 75 years, NTG has delivered world-class precision heat treatment services. Our state-of-the-art heat treatment furnace capabilities ensure components are processed to exacting standards in hardness, durability, and dimensional accuracy. Whether you need hardening heat treatment, heat treatment for gear manufacture, or annealing and tempering, NTG is equipped to meet your needs.

Our expertise spans a wide range of heat treatment processes tailored to enhance the mechanical properties of metals. We utilise advanced furnace technologies such as vacuum furnaces, salt bath furnaces, and induction heating systems to provide controlled heating environments that optimise material performance. By carefully managing parameters like temperature, heating duration, and cooling rates, we achieve desirable microstructural transformations that improve wear resistance, toughness, and strength.

At NTG, we understand that every component has unique requirements. That’s why we offer customised heat treat processes including case hardening to harden only the steel surface while maintaining a ductile core, neutral hardening for balanced properties, and surface hardening techniques like induction hardening to selectively treat gear teeth or critical areas. Our precision control over these processes ensures minimal distortion and residual stresses, preserving dimensional accuracy and extending component life.

Furthermore, our heat treatment furnace capabilities support a broad spectrum of alloy steels and low carbon steels, accommodating various industry standards and specifications. We maintain strict quality assurance protocols and metallurgical inspections to verify that each batch meets or exceeds expectations. With NTG’s comprehensive approach to heat treatment, your parts will achieve the maximum hardness and performance required for demanding applications.

What is a Heat Treatment Furnace?

A heat treatment furnace is a specialised industrial oven designed to heat metals to specific temperatures, control cooling rates, and manipulate microstructures. With the right furnace and process, materials gain properties like toughness, hardness, wear resistance, or ductility—critical in engineering, manufacturing, and gear making.

At NTG, our furnace capabilities include:

Ipsen sealed-quench gas carburising
Hardening
Tempering
Annealing
Normalising
Straightening
Quench pressing
Shot blasting

Heat treatment involves heating metal components to elevated temperatures where physical and sometimes chemical changes occur in the steel alloy’s crystal structure. By carefully controlling the heating and cooling cycles in a heat-treating furnace, we can optimise the mechanical properties such as hardness, strength, and corrosion resistance. These improvements are vital for components subjected to high stress, wear, or fatigue in demanding applications.

Different types of heat treatment furnaces, including vacuum chambers, salt bath furnaces, and induction heating systems, provide precise control over temperature and atmosphere. This control prevents oxidation and ensures uniform heat transfer throughout the metal surface. For example, vacuum furnaces maintain a protective atmosphere that minimises the formation of oxide films, preserving the integrity of the metal surface.

The heat treatment process can be tailored to produce only the surface hardened layer, known as case hardening, or to treat the entire component through methods like annealing or normalising. Case hardened gear components benefit from a hard, wear-resistant surface while retaining a ductile core to withstand impact and stress without cracking.

At NTG, we understand that heat treating is a critical and complex element of manufacturing that requires expertise in metallurgy, furnace technology, and process control. Our advanced heat treatment techniques ensure that each batch is rapidly cooled or slowly cooled as needed to achieve the desired microstructure and physical properties, meeting stringent industry standards.

By integrating these heat treatment processes with finishing operations such as quench pressing and shot blasting, we deliver components with optimal dimensional accuracy and surface integrity. This comprehensive approach results in parts that perform reliably in applications ranging from automotive gears transmitting power to aerospace components carrying motion under extreme conditions.

Benefits of NTG’s Heat Treatment Furnace Process

Optimised Hardness & Strength — Our hardening heat treatment methods deliver consistent, repeatable results, reducing subsurface flaws and ensuring performance.
Gear-Grade Precision — For gear manufacture, precision heat treatment engineering is essential; NTG ensures the proper case hardening, core hardness, and microstructure for smooth operation and long life.
Tailored Treatment Cycles — From tempering to annealing, we control the details: temperature, dwell time, cooling medium; matching material specifications and end-use.
Dimensional Accuracy — Quench pressing and straightening prevent warping. NTG ensures tolerances are maintained even after extreme heating.
Surface Integrity — Shot blasting and finishing after heat treatment rebuild surface quality, remove scale and enhance fatigue resistance.
Advanced Process Control — Utilising state-of-the-art monitoring systems, NTG precisely regulates furnace temperatures and atmospheres to achieve uniform microstructure transformations, critical for maintaining material consistency across production batches.
Versatility Across Materials — Our heat treatment furnace capabilities accommodate a wide range of materials including low alloy steels, carbon steels, and specialised alloy steels, allowing us to tailor processes such as carburising, nitriding, and induction hardening to meet diverse application requirements.
Energy Efficiency and Sustainability — NTG employs modern furnace designs and optimised process parameters to reduce energy consumption and environmental impact while maintaining the highest quality standards.
Comprehensive Post-Treatment Services — Beyond heat treatment, we offer complementary services including stress relieving, tempering, and precision machining, ensuring components meet all mechanical and dimensional specifications before delivery.
Expertise in Complex Geometries — Our team is experienced in heat treating components with challenging shapes and sizes, employing custom fixturing and process adjustments to minimise distortion and residual stresses.
Continuous Improvement and Innovation — NTG invests in ongoing research and development to refine heat treat processes, adopt emerging technologies, and deliver cutting-edge solutions that enhance component performance and lifespan.

Why Choose NTG for Heat Treatment Furnace Services

Proven Heritage Since 1945 — NTG has a long track record in supplying precision heat treatment for gear manufacture and general engineering.
In-house Advanced Furnace Technology — Our sealed-quench furnaces, quench pressing, and full annealing/normalising capability allow full control.
Quality Assurance & Certification — Every process is backed by quality checks, metallurgical inspection, and compliance with industry standards.
Custom Solutions — Whether you have small batches, high volume, or unusual geometries, we adapt cycles and equipment to match.
On-time Delivery & Support — From quoting to machining, finishing, and inspection, NTG offers comprehensive service, so you don’t have to coordinate multiple vendors.

Case Study – Gearbox Shaft Hardening for Offshore Wind Application

Client: Major renewable energy OEM
Challenge: A gearbox shaft needed case hardening to resist extreme wear and fatigue in an offshore turbine environment. Tight dimensional tolerances after treatment were critical to avoid misalignment under load.

Solution:

Utilised our Ipsen sealed-quench gas carburising furnace for case hardening, achieving the required case depth and surface hardness.
Followed by tempering and straightening processes to maintain dimensional tolerances.
Final shot blasting to remove surface scale and improve fatigue properties.

Result:

Delivered shafts within ±0.1 mm of tolerance.
Lifespan exceeded spec by 30%.
Client accepted within inspection schedule; no costly rework required.

Industries We Serve

Since our founding in 1945, Northern Tool & Gear has provided precision heat treatment furnace services to clients across a broad spectrum of industries, including:

Automotive & Motorsport
Oil & Gas / Energy (including offshore & renewables)
Agricultural Equipment
Aerospace & Defence
Gearboxes & Transmission Systems
Mining & Heavy Machinery
Marine Engineering
Rail & Locomotives

Get Started Today

If you’re looking for a heat treatment furnace partner who delivers in precision, reliability, and performance, NTG is ready to help. Contact us to discuss your material, volume, and tolerances, and we’ll propose the optimal treatment cycle – from hardening heat treatment to post-treatment finishing. Our team of experts will work closely with you to understand the unique requirements of your components and recommend the most suitable heat treatment processes, whether that involves batch furnaces for smaller production runs or continuous furnaces for high-volume manufacturing.

We leverage advanced furnace technologies, including vacuum furnaces and salt bath furnaces, to ensure precise control of temperature and atmosphere, enabling us to achieve consistent and repeatable results. By carefully managing parameters such as heating rates, critical temperature thresholds, and cooling methods like oil quenching or gas quenching, we optimise the microstructure and mechanical properties of your materials.

This meticulous approach enhances wear resistance, hardness, and toughness, ensuring your parts perform reliably in demanding applications. Additionally, NTG’s commitment to quality extends beyond heat treatment; our integrated post-treatment services, including tempering, annealing, and precision machining, guarantee that your components meet stringent dimensional and surface finish requirements. Partner with NTG to benefit from decades of experience, cutting-edge furnace technology, and a dedication to delivering heat treatment solutions that drive your success.