Stainless steel has attained widespread popularity in the manufacturing and construction industries, and that's not likely to change anytime soon. Stainless is an iron-based alloy containing various amounts of chromium, protecting it from rust.
It's a strong material that resists most liquid, chemical, and gaseous corrosion, making it the top choice of several industries, including the medical, food, and beverage companies, for its resistance to bacterial growth. And because it can stand up to temperature extremes, stainless steel is popular in the pipe and oil industry.
As its popularity grows, stainless steel welding applications will grow with it. However, welding this attractive metal is not without its challenges, so the following stainless steel welding guide will seek to answer the most critical and pertinent questions that professional welders and hobbyists might have about it.
Can stainless steel be welded?
The short answer is yes, you can weld stainless steel, but the process differs depending on how the finished piece will be used, its thickness, and the steel's finish. Although there are various methods for welding stainless steel, three of these—TIG, MIG, and stick welding--are the most common.
Each method will provide a somewhat different result, so it's essential to consider a few factors before choosing, such as the required appearance of the part, the welder's skill level, and any time constraints with the project.
As a general rule of thumb, TIG welding is the preferred method on stainless steel, one of the least forgiving materials, since it provides attractive and controlled welds. However, it is slower than the other two and demands an experienced welder with a first-rate technique.
Is it dangerous to weld stainless steel?
Welding stainless steel is not without safety concerns. Producing stainless steel requires using chromate chemicals. During welding, the chemicals convert into hexavalent chromium, causing a host of potentially dangerous side effects: eye damage, skin irritation, occupational asthma, liver damage, and even certain cancers.
Working with stainless steel means taking the proper preventative measures to protect welders from these fumes. The correct ventilation systems, fume extraction equipment, and personal protective equipment are essential elements in minimizing the safety risks and protecting the long-term health of the welders.
What's the best welding machine for stainless steel?
Because it offers versatility and high-quality welds, TIG is typically the first choice for stainless steel welding, and it creates a low-heat input, making it ideal for thinner metals. One of the best and most reasonably priced machines on the market is the TIG225X AC/DC Welder with Pulse from PrimeWeld. With a complete range of adjustments, the machine allows its operators to fine-tune their arc characteristics, resulting in attractive stainless-steel welds.
As an alternative, the MTS200 3-in1 welder from PrimeWeld covers all your bases with TIG, MIG, and stick capabilities. It is perfect for use on stainless steel, and it includes features that make it user-friendly for the less experienced welder.
How does TIG welding on stainless steel work?
TIG welding requires you to focus on heat and the filler metal initially. Of course, heat is an essential aspect of the welding process since the heat needed to melt the stainless steel comes from an arc that's struck and maintained between the stainless-steel workpiece and a tungsten electrode. The non-consumable electrode undergoes minor wear.
Austenitic stainless steels are in the 300 series, designated 301, 302, 303, and 304, and require the 308L filler rod. Sometimes 304 stainless is protected by adding molybdenum, so 316 or 316L TIG Rod is better. Type 321 stainless steel alloy uses 347 welding wire.
Welding stainless steel requires either a Direct Current Electrode Negative (DCEN) or Direct Current Straight Polarity (DCSP) mode. It also typically involves the flow of inert shielding gas to protect the arc zone from contamination and maintain a stable arc. While argon is the choice for a shielding gas in many cases, the type of stainless steel will ultimately be the deciding factor.
TIG welding on stainless steel is a process on which many industries depend. When done correctly, it provides professionals and hobbyists alike with the ability to have excellent results and keep their projects and themselves safe at the same time.
Stainless steel welding guide for MIG welding
Metal inert gas (MIG) welding uses a continuously-fed solid wire electrode and a shielding gas to protect the weld pool from contamination in the atmosphere. Some welders prefer MIG for welding stainless steel because of the relative simplicity of the process. But before you get started, consider some MIG welding factors that will determine whether your stainless-steel welding project is successful.
- Get the right inert shielding gas mixture: Pure argon or a blend of argon and other minor gases like helium and carbon dioxide work well for exotic metals like stainless steel. Also, MIG welding stainless steel requires a slightly higher flow rate of between 14 and 16 liters per minute. The ER308L electrode is commonly used for welding stainless, and the gas mixture when using this electrode is 90% helium, 7.5% argon, and 2.5% carbon dioxide.
- Clean the weld joint: It's always a good policy to start with a clean weld surface.
- Set up the torch: Get the wire from the spool to the torch's tip with only 1/4" of wire visible at the end of the torch. Next, turn on the shielding gas.
- Get the correct angle: Make sure the flame hits the required area by having the torch at a 30-degree angle from the end of the joint. The travel angle should be between 5 and 15 degrees with the gun at 90 degrees, with greater angles of 45 to 70 degrees when welding T-joints or lap joints.
- Draw the weld bead toward the end of the joint while using moderate speed and power to avoid spatters.
Can you weld stainless steel using a gasless welder?
Yes, you can weld stainless steel with a gasless MIG welder as long as you use self-shielding flux-cored wire that eliminates the need for shielding gas. PrimeWeld's MIG160 Portable Flux Core Welder is an example of a lightweight machine that works as well outdoors as it does in the shop. Using hollow wire with flux material contained within, it's the perfect setup for anyone who can't or doesn't want to use a shielding gas.
Is it possible to weld thin stainless steel, say .5 mm?
Yes, it is possible by using a TIG welder and starting with a clean surface and a good fit-up. Conventional guidelines indicate one amp for each .001" thickness. Since .5mm is .020", 20 amps should be in the ballpark. Use a 1/16" diameter electrode that's either 2% thoriated tungsten or 2% lanthanated tungsten, and grind it to a needlepoint. Weld with 308L stainless steel filler metal with a 1mm or 1.5mm diameter.
What's the reason for black welds when welding stainless steel?
Black welds generally indicate that the weld was exposed to oxygen while still hot. Various causes include:
- Welding with too much current
- The travel rate is either too fast or too slow
- Using the wrong shielding gas or inadequate gas flow
- Wind or drafts disturbing the shielding gas flow
Can you TIG weld stainless steel to titanium?
Some experienced welders will answer with a flat "No" to this question. However, many say you can get a solid weld with titanium and stainless steel when using 99.999% pure Argon gas with the TIG (or MIG) method.
Do you still have questions about stainless steel welding applications?
Talk to the experts at PrimeWeld for the answers not provided in this stainless-steel welding guide. We are the leaders in affordable welding tools and using the best method for your application.
Fill out our convenient contact form, call us at 856-537-4368, or send a message to Info@primeweld.com.