TIG Weld Stainless Steel With Chill Blocks: Heat Management in Orbital Welding

Stainless steel and heat have a tricky relationship, high heat can cause a lot of issues. The effect is primarily observed in the form of rust and corrosion due to the loss of oxidation resistance. This is why the welding of stainless steel requires extreme control. This control can come in the form of precision input or the use of external thermal management components. 

A chill block has been seen as an effective way to position and hold the workpiece steady during welding, while also ensuring heat management. Industries can also make use of external welding chillers along the workpiece to keep the heat in check. 

Let's explore the different thermal management solutions used to improve the reliability of welds during orbital TIG (Tungsten Inert Gas) welding of stainless steel.

How Heat Affects Stainless Steel

When working with stainless steel tubes, industries expect tensile strength, corrosion resistance, temperature resistance, and metallurgical stability. However, when this metal is exposed to heat, some of its metallurgical properties change. Welding without proper control can lead to excess localized heating, evaporating away chromium as hexavalent chromium. This leads the stainless steel to be vulnerable to rust and corrosion.

Additionally, uneven application of heat when welding can cause the metal to distort, damaging its mechanical strength. In stainless steel, hydrogen cracking and embrittlement can also be major issues. This is the result of hydrogen diffusion into the metallic weld pool at high temperatures which creates cracks and voids during cooling.

Controlled heat input and careful heat minimization techniques during welding are effective solutions to these problems. 

TIG Weld Stainless Steel with Chill Blocks

A unique feature of a TIG weld is that the process produces more heat through a narrow, concentrated arc compared to other welding forms such as the MIG (Metal Inert Gas). Therefore, it is important to note that the temperature does not exceed the interpass temperature (generally 150°C for austenitic stainless steel). Beyond this temperature, there is a high chance that the heat will burn through the backside of the workpiece, damaging it. As a preventive measure when TIG welding, the copper or aluminum chill blocks can be used as a heat sink.

Chill blocks are an effective heat management tool that holds the workpiece in place while absorbing excess heat. The advantage of TIG welding stainless steel with chill blocks are:

• Fast and effective cooldown of stainless steel welds to prevent overheating, heat distortion, or other weld defects
• Economic option compared to extensive cooling units
• Ideal positioning of the workpiece

By keeping the weld temperature within the specified heat parameter, these chillers facilitate high-quality welds of small-sized stainless steel tubings.

This feature is akin to orbital welding’s ability to precisely control the heat input. Chill blocks are not needed if you switch to orbital welding. The advanced welding system with parameter control is suitable for manufacturers to enhance their welding efficiency in a highly productive environment. When paired with external chillers, the results are sure to be of high quality.

Thermal Management with Orbital Welding of Stainless Steel

For a wide range of stainless steel tubing sizes, Swagelok offers appropriate weld heads and power supply solutions. This selection of components for orbital welding offers effective weld parameter control, including heat control and travel speed, so you do not have to worry about thermal management while working with critical stainless steel tubings. The power supply unit such as the M200 orbital welding system paired with the air- or water-cooled orbital weld heads, provides the right amount of heat input required for complete penetration. In addition, the weld head solutions also include cooling plates which dissipate the heat from the weld head to prevent excessive localized heating.  

With Swagelok’s orbital welding solutions and external cooling systems, heat management will be precise and controlled for your TIG stainless steel welds.

To find out more regarding TIG welding stainless steel with chill blocks or other external cooling systems, and how Swagelok Northern California’s orbital welding solutions will help assure heat management for your fabrication process, contact our team today by calling 510-933-6200.

About Jason Burns | Technical Services Manager

Known to customers and Swagelok Northern California associates as the Swagelok Answer Man. Jason spends his work days answering customers' technical questions about Swagelok products and tools and training customers on how to install and use them.