Your Guide to Industrial Stainless Steel Welding Practices

Network of piping showing stainless steel welding

Stainless steel has transformed industries since its invention in the 1900s. Excellent mechanical properties, corrosion resistance, and cleanliness have contributed to its versatility and enabled the metal to be used in manufacturing products as diverse as surgical equipment and spacecraft. Because stainless steel is a popular material across wide-ranging manufacturing environments, it must adhere to many fabrication and manufacturing standards. As such, welding stainless steel also requires thorough consideration.

Various grades of stainless steel require different parameters during welding and a variety of welding process implementations. When performed with orbital welding, operators can more easily overcome the many challenges of stainless steel welding and obtain high-quality results. This article will explore the parameters, welding types, and challenges of stainless steel welding.

Different Methods of Welding Stainless Steel

Stainless steel is an alloy of iron and carbon, containing at least 10.5% of chromium. It is resistant to rust and possesses excellent heat-resistance properties. However, the presence of chromium also adds to the challenge of stainless steel welding. Depending on the chemical composition of the stainless steel, it can also be divided into specific types: austenitic, martensitic, ferritic, and duplex.

Stainless steel welding is particularly challenging because it requires welders to consider different material properties, chemical compositions, lattice structures, and weld preparation requirements. To address the welding needs of these various stainless steel types, welders tend to choose the following welding processes:

SMAW (Shielded Metal Arc Welding): SMAW, also known as stick welding, utilizes a consumable electrode with a flux coating. The flux coating dissolves during welding and evaporates as a vapor that acts as a shielding gas to protect the weld area. It is the most basic welding method utilized widely for maintenance and repair.
FCAW (Flux Cored Arc Welding): FCAW uses a flux-cored, wire-fed, consumable electrode to perform the weld. The welding mechanism is similar to SMAW; however, due to its automatic/semi-automatic weldability, it is suitable to use where high-speed welding is required.
GMAW (Gas Metal Arc Welding): GMAW, or MIG (Metal Inert Gas), enables welders to form an electric arc to create a fusion between the base metal and wire-fed electrode. Due to the inert shielding gas, the weld formed is pure when compared to other welding processes.
GTAW (Gas Tungsten Arc Welding): GTAW, or TIG (Tungsten Inert Gas), utilizes a tungsten electrode, filler metal, and inert shielding gas to create a clean and high-quality weld. This is a commonly used method for stainless steel welding. Operators have excellent control over the weld parameter and can perform complex welds perfectly.
PAW (Plasma Arc Welding): Similar to GTAW, PAW also utilizes a tungsten electrode to form an arc. The difference is that the electrode is placed inside the torch body, and the plasma is forced outside through the constriction such as the nozzle. This welding process is suitable for narrow groove welding and can produce a weld with deeper penetration.
LBW (Laser Beam Welding): In this welding process, the two pieces of metal are joined using a laser. Although it is a complicated welding process, it is used widely in high-volume weld applications for its speed, penetration, and narrow gap weldability.

Stainless steel welding processes focused on speed and volume may prefer LBW and FCAW processes. However, GTAW is more likely suitable when the goal is to produce high-quality results with excellent metallurgical properties of the welded component. For stainless steel, conventional GTAW provides the following advantages:

Stable arc produces smooth and high-quality weld.
Control of heat input minimizes distortion and defects like pores and voids.
Reduces the need for filler material.
Shielding gas reduces contamination and prevents loss of corrosion resistance due to oxidation.
Weld parameter control facilitates precise depth of penetration and narrow fusion zone.

These orbital welding attributes help provide safe and efficient welding options for critical pipeline system technicians.

Orbital Welding Eliminates Stainless Steel Welding Challenges

Orbital welding can help manufacturers achieve the best result from the various stainless steel weld processes. As a mechanized welding process, orbital welding provides weld parameter control and monitoring, which can help solve stainless steel welding challenges such as:

Toxic fumes: Exposure to carcinogens such as hexavalent chromium is a concerning issue in manual welding due to the chromium content in stainless steel. However, orbital welding is automated and allows operators to remotely monitor and optimize the weld so that their exposure to toxic fumes is minimized.

Weld defects: Different stainless steel grades have different thermal conductivity or melting temperatures. Orbital welding can help optimize the weld parameters to suit the weld metal requirement. For instance, austenitic stainless steel has a low thermal conductivity and prefers a low heat input for welding. With support from the controller and precision weld heads, orbital welding can provide accuracy and control in weld input. This facilitates the elimination of common weld defects such as contamination, lack of fusion, grain growth, embrittlement, and cracking.

Sanitary requirements: Stainless steel is used in most pharmaceutical or food-grade industries that require a hygienic environment. The consistency provided by orbital welding enables clean and smooth high-quality welds to reduce the odds of contamination.

To obtain the best result from orbital welding, you must also understand how weld preparation depends on the stainless steel grade.

Resources: Welding Different Stainless Steel Grades

To understand stainless steel grade basics—and their welding requirements—explore the following resources:

Adapting Orbital GTAW for High-Quality Stainless Steel Welding

Orbital GTAW can help industries meet high-quality welding and manufacturing standards. For optimal performance across stainless steel grades, orbital GTAW enables controlled heating and cooling provisions that minimize heat distortion issues—especially in thin stainless steel tubes. Additionally, excellent shielding provides an opportunity to create clean and pure welds for sanitary applications. And orbital welding’s automated process and remote monitoring capabilities can help increase the weld speed and efficiency while eliminating potential health hazards for welders. For safe and high-quality stainless steel welding, orbital GTAW provides an unparalleled option.

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Arc Machines, Inc. is a leading orbital welding technology provider with decades of industry experience. Our range of orbital welding solutions can help you meet your industry standards for stainless steel welding. For inquiries regarding products, contact sales@arcmachines.com. Contact us today to learn more.