Welding Stainless to Mild Steel with 7018 [In-Depth Guide]

The success of welding depends on the quality of an electrode and its’ compatibility with the two metals. Recently, the usage of the 7018 electrodes has spiked to a great extent. But does this electrode go well with stainless steel and mild steel?

Don’t get tensed. As a welding expert, this article will reveal if welding stainless to mild steel with 7018 provides a satisfactory output. So, let’s get started.

What does e7018 Electrode Mean?

If you think e7018 is just a random number, you are in the dark. Every number has its significance. Here is what the e7018 electrode means:

EE denotes Electrode

70- This number represents the tensile strength an electrode can produce. For the e7018 electrode, the rod produces a weld bead with a minimum of 70,000 psi tensile strength.

1- This numeric refers to the electrodes’ possible welding position. If it is 1, the electrode can weld in all positions. For 2, an electrode can weld on flat and horizontal fillets only.

8- This number indicates that the electrode rod has low hydrogen potassium and low iron coating. This rod can be used with all currents (AC, DC)

Is It Hard to Stick Weld Stainless Steel to Mild Steel?

It is not hard to stick weld stainless steel to mild steel if you use the correct electrode. With E308, E309, or E310, you can easily stick weld stainless steel to mild steel. But with the E7018 electrode, the output of stick weld stainless steel to mild steel is disastrous.

Generally, an e7018 electrode produces a low corrosive bead. With lower tensile strength, the main goal of welding fails to deliver its actual result.

Characteristics of Mild Steel and Stainless Steel

If you do welding regularly, you should be aware of the welded material properly. Mild steel and stainless steel are one of the most used metals. Let’s get to know about mild steel and stainless steel.

Here are the characteristics of mild steel:

  • High tensile and impact strength
  • Exceptional ductility and is a low-brittle material.
  • Magnetic by nature
  • Excellent malleability.
  • Not suited for heat treatment.

Here are the characteristics of stainless steel:

  • Corrosion and temperature resistance.
  • Higher tensile strength.
  • Easy formability and fabricability.
  • Very durable and environmentally friendly.

What Metal can 7018 Weld?

7018 can be used to weld every form of carbon, from low to high, and low alloy steel. Basically, E7018 has low hydrogen potassium. So, it should only be used where great tensile strength is required.

E7018 electrode produces bead with high ductility. Despite being low-brittle, the bead E7018 generates, doesn’t crack easily.

How to Weld Stainless Steel to Mild Steel Using 7018 Rod

Now that you set your hearts upon using a 7018 rod to weld stainless steel to mild steel, let’s explore the detailed procedure of welding stainless steel to mild steel with 7018.

Here are the steps to weld stainless steel to mild steel using a 7018 rod:

Clean the Metals

The golden rule of successful welding is to free the material from all contaminants. The contaminants can be in the form of oil, grease, oxides, rust etc. As every material has different chemical components, the standard procedure for cleaning the metals is other.

Here is how you can clean stainless steel:

To remove oil or grease from stainless steel, use a rag soaked with alcohol (preferably acetone).

But the real challenge is when there are oxides coating on stainless steel. Don’t worry. I will make your challenge easy.

You can either perform sandblasting with silica or use a stainless wire brush to remove oxides from stainless steel. Yes, you cannot remove 100% oxides, but you will be 99% there to remove this contaminant.

Here is how you can clean mild steel:

The process is somewhat similar to cleaning stainless steel. Just perform sandblasting or use a wire brush.

Just remember, never use chlorinated chemical products.

Pro tip:- Before starting to weld, ensure the metals have 0% moisture.

Prepare the Joints

Now, it’s time to have a perfect setup so that you need the least amount of weld metal and don’t need a second attempt.

Position stainless steel and mild steel symmetrically. If the metals are 3/16” thick, create a 30-degree single V joint and bevel it. Metals thicker than 3/16” would require a double V joint. I created a V joint because a V joint requires less weld metal.

 Pro tip:- keep the root gap at 1/16” and root face at 1/16”

Set the Current Reading

Excess current flow will tamper the weld metal with carbon. So, it’s essential to know the correct amperage number.

As you are using E7018, you can set the current at 125A, not more than that. But if you struggle to sustain that current, use at least 100A. You must always start with the lowest amount of current and gear it up.

Pro Tip:- Tack both stainless steel and mild steel at a 2” distance to avoid distortion.

Weld at the Right Angle

So, now, you are all set to perform welding stainless steel to mild steel with 7018; it’s crucial to weld at the right angle.

For the E7018 electrode, try to weld at 60 degrees to avoid slag incursions and irregular beads. However, the traveling angle has to be within 5-10 degrees.

If you follow everything I have mentioned, I genuinely believe you will have a fantastic experience welding stainless steel to mild steel with 7018. And, you will get an outstanding output too.

What Welding Rod do I Use to Weld Stainless Steel to Mild Steel?

An E309L-16 or an E312 is the most suitable welding rod you should use to weld stainless steel to mild steel. To weld stainless steel to mild steel, you need a welding rod capable of producing high tensile bead and highly corrosive and temperature resistance. 

E309L-16 welding rod is rich in chromium and nickel content. With this electrode, there is a minor possibility of hot cracking.

But the fact is E309L-16 is costly. So you can go for E312 alternatively.

FAQs

Can you weld different types of stainless steel together?

You can weld different types of stainless steel together, but both of them have to be in the same family. Like two stainless steels of the 300 series are compatible with each other. You can weld 300 and 400-series stainless steel together, but it is not recommended.

Is 7038 welding rod AC or DC?

7038 welding rod works with both AC and DC.

Last Words

Welding stainless steel to mild steel with 7018 is possible but not recommended. E7018 is suitable for low alloy steel, and stainless steel doesn’t fall into this category. If you want to use E7018, go for low, medium, or high carbon and low alloy steel. But if you intend to weld stainless steel to mild steel, E309L-16 is the electrode you should prefer

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