How Many Amps to Weld 3/8 Stainless Steel? Essential Guide to Welding, Types & Factors
Published on: November 22, 2024 | Last modified: January 17, 2025
By: Joe Carter
3/8 stainless steel is a type of metal that’s 0.375 inches (9.53 Mm) thick. It’s known for its durability, corrosion resistance, and strength.
You may be wondering how many amps to weld 3/8 stainless steel. It’s crucial to know this because using the wrong amperage can lead to weak welds or damage to the material. In my experience, I’ve seen welders struggle with this, affecting the quality of their work and the longevity of their projects.
In this guide, we’ll go over several important topics: what 3/8 stainless steel is, its types and weldability, the steps to weld 3/8-inch stainless steel, and the factors that affect amperage. We’ll also tackle similar questions like how many amps to weld 3/16 steel or how many amps to weld 1/4 steel, ensuring you have complete insight into the process.
Contents
- How Many Amps to Weld 3/8 Stainless Steel?
- What is 3/8 Stainless Steel?
- Types Of 3/8 Stainless Steel and Their Weldability
- Steps to Weld 3/8-inch Stainless Steel
- Factors Affecting Amperage for Welding 3/8 Inch Stainless Steel
- Welding Techniques for 3/8 Stainless Steel
- Amperage Settings Based on Joint Configuration
- Frequently Asked Questions (FAQs)
- Conclusion
- Additional Reading
How Many Amps to Weld 3/8 Stainless Steel?
3/8 stainless steel is a robust material often used in construction. To weld it, you need about 200 to 300 amps. This depends on your welder type. Typical applications include piping, automotive, and structural components.
What is 3/8 Stainless Steel?
3/8 stainless steel refers to a thickness of 0.375 inches (9.525 Mm). It’s used in applications ranging from kitchen equipment to industrial structures. Stainless steel typically contains iron with at least 10.5% chromium, which enhances its rust resistance. Adding nickel and molybdenum improves its strength and corrosion resistance, especially in harsh environments.
Now, how many amps are needed to weld 3/8 stainless steel? Based on the material’s thickness, I’ve learned that the amperage is crucial for achieving proper fusion without burning through.
For welding steel like this, it’s essential to get the amps just right. In my early welding days, I often wondered about the amps needed for 1/4 inch or even 1/2 inch thick sections. Each thickness requires precise settings; welding 3/8 stainless steel demands a specific approach. Learning to dial in the right amps significantly improved my weld quality.
Types Of 3/8 Stainless Steel and Their Weldability
What are the types of 3/8 stainless steel regarding welding?
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Austenitic Stainless Steels
Austenitic stainless steels are versatile and corrosion-resistant. For this type, you typically need about 150-200 amps. Set your MIG welder between 150 and 200 amps, adjusting for travel speed and joint configuration.
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Ferritic Stainless Steels
Ferritic steels offer good corrosion resistance but may be less ductile than austenitic steels. Aim for around 130-180 amps for welding. Set your welder to about 130 to 180 amps, and use a filler that matches the ferritic grade.
When working with galvanized steel, it’s crucial to consider safety measures due to potential hazards from zinc fumes during welding. For more information on the risks of welding galvanized steel, ensure you are adequately informed.
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Martensitic Stainless Steels
Martensitic steels are known for their hardness and strength. Post-weld annealing is often needed. Use 100-150 amps when welding this type by adjusting your welder to about 100 to 150 amps, especially with the TIG method.
For those embarking on welding projects, sourcing quality metal is crucial, and it’s important to explore where to buy metal for welding.
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Duplex Stainless Steels
Duplex steels combine austenitic and ferritic properties for high strength. Aim for 120-160 amps when welding. Set your welder to about 120 to 160 amps and maintain a smooth arc length.
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Precipitation Hardening Stainless Steels
These steels are strong and can be hardened through heat treatment. Expect to use around 150-170 amps for welding. Set your MIG welder to approximately 150 to 170 amps, being mindful of heat input to avoid distortion. Proper storage of welding rods is crucial for optimal performance, ensuring consistent quality in your welding projects, as detailed in how to store welding rods.
You should now have a good understanding of various types of 3/8-inch stainless steel and their weldability. In the next part, we’ll discuss steps to successfully weld 3/8-inch stainless steel.
Steps to Weld 3/8-inch Stainless Steel
Now, we’ll cover the steps for determining how many amps you need to weld 3/8-inch stainless steel. Follow these carefully for the best results!
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Calculate Amperage
To weld 3/8-inch (9.5 Mm) stainless steel, start by determining the correct amperage. You generally need about 1 amp per 0.001 inch of thickness. So, for 3/8-inch, that’s approximately 375 amps. This figure varies based on the welding process. A key factor in this calculation is the type of primer used, as using a weld through primer can influence the efficiency and quality of the weld.
Factors like metal type, joint design, and travel speed can affect your amperage. For instance, if you’re using MIG welding, adjust amps according to wire feed speed and voltage. I like to use a welding amperage chart for quick reference!
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Choose Welding Method
Decide whether to use MIG or TIG for your weld. MIG is often quicker and easier for thicker metal like 3/8-inch stainless, but TIG offers better control. If you choose MIG, use a shielding gas mix of 75% Argon and 25% CO2 for cleaner results. Adjust your amps accordingly between the two processes!
Each method requires slight adjustments to the amps. For example, when TIG welding, I often reduce my initial setting by about 10% to manage heat and prevent burn-through on the material.
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Set Your Machine
Next, input your calculated amperage into your welding machine. For stainless, if you’re at the 375-amp mark, set it to a constant voltage. It’s crucial to fine-tune the machine based on your welding process. If the machine seems off at first, don’t hesitate to make slight adjustments! Mastering the technique is essential for ensuring precision, so it’s beneficial to understand how to weld a straight bead.
After my experiences with settings, I learned that starting slightly lower and gradually increasing amps works best. If it’s too cold or hot, you can adjust without starting over. Every machine is different, so take your time to get it right.
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Test on Scrap Material
Always test your settings on scrap material before proceeding with the actual weld. This can save you from costly mistakes. Use 3/8-inch (9.5 Mm) scrap stainless steel for a test weld. Check for penetration and overall appearance; it indicates whether you need more or less amperage. Understanding the quantity of 1/8 7018 welding rods per pound can help in planning and managing resources more efficiently. Find more details about 1/8 7018 welding rods.
If the weld looks inconsistent, it’s a sign to tweak your settings. For instance, a pitted or poorly fused joint means the amp setting was too low. Testing allows you to refine your technique.
We have now covered the process of welding 3/8-inch stainless steel. Next, we will examine factors that influence welding amperage.

Factors Affecting Amperage for Welding 3/8 Inch Stainless Steel
What factors influence the amperage needed for welding this thickness?
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Material Thickness
Welding 3/8 inch (9.53 Mm) stainless steel generally requires about 150 to 200 amps. Thicker materials need more heat for proper penetration and fusion.
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Welding Position
Welding in a flat position usually requires fewer amps than vertical or overhead positions. This can lead to adjustments of 10-20 amps based on your position.
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Electrode Type
The choice of electrode matters! For example, a 6010 electrode may need different amperage than a 7018. I once selected the wrong type, causing poor fusion and increased defects. Know your electrode specs—it can drastically alter your amp needs!
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Arc Length
A shorter arc length focuses heat, requiring fewer amps. If you pull away too much, you may need an additional 10-15 amps for adequate penetration.
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Travel Speed
Speeding through the weld reduces heat input. Traveling too fast may require higher amperage to compensate for the cooler weld joint.
That covers the elements influencing amperage for welding 3/8 inch stainless steel. Let’s now take a look at welding techniques for 3/8 stainless steel.
Welding Techniques for 3/8 Stainless Steel
Let’s dive into the welding techniques for 3/8 stainless steel that can impact amperage requirements.
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MIG Welding
MIG (Metal Inert Gas) welding is popular for 3/8 stainless steel. It allows for continuous feeding of filler material, making it faster. For this technique, set your welder between 200 to 300 amps, as understanding welding fundamentals can significantly enhance your welding skills.
Selecting the right equipment for your project might also require understanding generator size requirements for welders.
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TIG Welding
TIG (Tungsten Inert Gas) provides precision and control. It requires about 180 to 250 amps. You can use a smaller filler rod for refined control, which is important for thinner sections. I typically prefer this for complex joints.
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Stick Welding
Stick welding works well too. Expect to set your welder around 150 to 220 amps. It can struggle on thinner materials, but it’s great for thick sections of 3/8 stainless. Just make sure to pick the right electrode!
We’ve wrapped up various welding techniques for 3/8 stainless steel here. Next up, we’ll look at amperage settings based on joint configuration.

Amperage Settings Based on Joint Configuration
Joint design plays a crucial role in determining the necessary amperage. Check out these configurations:
Joint Configuration | Amperage Range (amps) | Comments |
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Butt Joint | 200-250 | Requires strong penetration; higher amps needed. |
T Joint | 220-270 | Ensure good fusion on both sides; adjust if needed. |
Lap Joint | 180-230 | Heat distribution is key; start at lower amps. |
Corner Joint | 190-240 | Watch for excess heat; may need fine-tuning. |
Frequently Asked Questions (FAQs)
Now let us look at some of the questions I typically get asked.
How Many Amps Do You Need to Weld Stainless Steel?
You will need between 90 to 150 amps to weld stainless steel, depending on the thickness. For example, 1/8 inch (3.2 Mm) stainless steel generally requires around 90 amps, while 1/4 inch (6.4 Mm) may need closer to 130 amps to ensure proper penetration and a strong weld.
What Voltage Do You Need to Weld Stainless Steel?
For welding stainless steel, you’ll typically use a voltage range of 18 to 25 volts. The specific voltage will vary based on the amperage and thickness of the material you are welding, affecting arc stability and penetration quality.
How Thick Can 200 Amps Weld?
A 200 amp welder can weld steel up to 1 inch (25.4 Mm) thick, depending on the process used. TIG and MIG processes can handle thicker materials better, making them suitable for industrial applications and heavy-duty projects. Mastering techniques for thinner metals requires a different approach which is essential when you need to know how to weld thin metal.
How Many Amps Does It Take to Stick Weld Steel?
To stick weld steel, you’ll generally need between 70 to 150 amps. The exact amperage depends on the electrode size and steel thickness—using a 1/8 inch (3.2 Mm) electrode calls for about 100 amps for excellent performance.
How Many Amps to Weld 1/4 Steel?
You’ll need about 130 to 170 amps to weld 1/4 inch (6.4 Mm) steel effectively. This level of current ensures proper penetration and reduces the chance of weld defects, which can compromise the joint strength.
Conclusion
We covered how to weld 3/8 stainless steel, its different types and weldability, the necessary steps for welding, and factors that affect amperage. We also answered frequently asked questions to ensure clarity. Each part of the article aimed to give you a solid understanding of welding techniques for this type of steel.
To weld 3/8-inch (9.53 mm) stainless steel, you’ll generally need around 150 to 225 amps. Remember, the specific requirements can vary based on factors like joint design and position. Don’t hesitate to get in touch for further assistance if you need more help with this topic or any related queries.
For additional insights and resources, feel free to explore more at What is Welding. We hope you find the information valuable and conducive to your learning journey.
Additional Reading
- American Welding Society. (2015). AWS D1.1/D1.1M: Structural Welding Code – Steel. Miami, FL: AWS.
- American Welding Society. (2020). AWS Welding Handbook: Welding Science and Technology (Vol. 1). Miami, FL: American Welding Society.
Joe Carter is a retired welding professional with over 40 years of hands-on experience in the industry, spanning ship repair, structural welding, and even underwater projects. Joe is a master of MIG, TIG, and Stick welding. Passionate about mentoring the next generation of welders, Joe now shares his decades of expertise and practical insights to help others build rewarding careers in welding.
Amperage, MIG Welding, Stainless Steel, TIG Welding, Welding, Welding Techniques