Flame Heat Treatment for Fabrication

Linde offers numerous heating and surfacing technologies to support metal fabrication operations and when it comes to gas-enabled applications, our engineers are among the most knowledgeable in the world. Discover how we can help optimise your heat treatment processes by improving quality and efficiency.

Common problems in metal fabrication
Internal stresses cause shrinkage, warping or movement in metal or alloys and are common problems when welding or cutting. External stains like scratches, abrasions or gouges are not only an aesthetic issue but can lead to corrosion. To create a premium quality product that is free from damage or deterioration, a variety of flame heating techniques are required in metal fabrication. They are used to initially prevent or repair defects.

Mastering complex heating tasks with various flame heating techniques
Examples of heating include flame straightening, flame hardening, hot forming and heating in conjunction with welding. In gas welding, the flame is used for melting purposes. In the case of flame-sprayed coatings, sometimes a flame fusing process is necessary.

Typical fuel gases for flame heating
Hydrocarbons such as methane, ethylene, acetylene, propane, and propylene or hydrogen are used as fuel gases for flame heating. Many different factors must be considered when choosing a fuel gas for flame treatments depending on the desired properties or outcome. The operator may require rapid local heating, for instance, or homogenous heating of the entire workpiece. Hydrocarbons such as methane, ethylene, acetylene, propane and propylene or hydrogen are used as fuel gases for flame heating.

The flame temperature and intensity depends on the fuel gases used and the oxygen mixing ratio. Acetylene and hydrogen flames can be set to a normal or reducing atmosphere whereas all other common fuel gases have an oxidising flame.

LINDOFLAMM^®: The solution for all your heating requirements
Linde delivers a wide range of heating and surfacing process technologies capable of optimising manufacturing process performance and results regardless of your individual manufacturing challenges. Our LINDOFLAMM^® range of special acetylene burners provides tailored solutions for all flame straightening, preheating, postheating, hot forming, brazing and flame hardening process challenges across the widest range of materials. In addition, we complement our state-of-the-art supply solutions and hardware with excellent consulting and customisation services ensuring you maximum return on investment.

Benefits at a glance:<ul><li>Easy to apply – can save material integrity </li><li>Reduces rework and re-conditioning of products </li><li>Reduces risk of hydrogen embrittlement </li><li>Most effective with acetylene as fuel gas <ul><li>heating time reduced by up to 20% </li></ul><ul><li>rapid annealing of desired areas </li></ul></li><li>Burner selection adapted to customer demands </li><li>Customised gas supply solutions</li></ul>The main heating applications supported by LINDOFLAMM: Preheating/Postheating: Certain materials must be preheated before welding to avoid hardening cracks. After welding, stress relief heat treatment may be necessary to reduce welding stress.Flame Straightening: This technique is employed to change or restore the shape of parts that have become distorted. When a workpiece is heated beyond its yield limit and its surroundings prevent expansion, plastic deformation will occur. Once cooled, the material will shrink in size. A skilled operator can heat isolated spots, lines or wedges to straighten the deformation.Melting: This involves soldering, brazing and fusing of sprayed coatings as well as flame welding.Hot Forming: The part to be formed is heated locally. An external force is then applied to form the part. For example, necking out pipe branch stubs.Shrink Fitting: To achieve a change in size used for shrink fitting to securely fit shafts/bearings. Liquid nitrogen can be used for cooling (shrinking) and an oxy-acetylene flame for heating (expanding). Stress Relief Heat Treatment: This may be necessary after welding.Metal Structure Changes: This involves flame hardening. Selecting the right fuel gas Depending on the desired properties or outcome, many different factors must be considered when choosing a fuel gas for flame treatments. For example the operator may require rapid local heating or homogenous heating of the entire workpiece. Regardless of your flame treatment application, the right gas and supply solution can enhance both quality and productivity. Our wide LINDOFLAMM portfolio uses acetylene as fuel gas and can be perfected to suit your needs.Customised to your individual needs For particularly complex heating challenges, we develop and manufacture tailored systems supporting partially or fully automated heating processes. Depending on individual needs, these systems offer functions such as automatic ignition, flame monitoring, and temperature control and documentation.All-round offering Precaution and repair steps within the metal fabrication process can be costly and time-consuming. With Linde you will benefit from decades of experience and a proven track record. Complementing our broad range of special burners, our engineers can support you with their in-depth know-how and application excellence, helping you select the optimum gas supply system, set-up and parameter settings.

Flame Heat Treatment for Fabrication Heating techniques enhance quality and productivity – Linde technology raises the performance bar with highest cost-efficiency