Can You Weld Zinc Plated Steel?

One of the commonly asked questions is, ‘can you weld zinc plated steel?’ 

Regarding the possibility of welding zinc plated stainless steel, the answer is yes. 

As a hobby welder, you can weld zinc plated steel and smile away with an enlarged pocket. But you know what, that’s not enough. 

Welding zinc-plated steel is a sensitive topic because, aside from the curiosity about the possibility, it also raises questions about potential health hazards.

To successfully and safely weld zinc plated steel, you need to observe some critical guides and steps to avoid damaging your health.

This post includes:

• The distinction between zinc and steel
• Their reactions under different temperatures
• The materials needed for such welding
• Step-by-step guides to the process
• The safety measures and precautions for welding zinc plated steel

What Is Steel, And Why Is It Plated?

Steel is an alloy and is made up of some quantities of carbon which aid to improve its strength and fracture resistance compared to other kinds of iron.

Despite its strength, steel carbons are vulnerable to oxidation, a reaction caused by the exposure of steel to moisture, which leads to wear, tear, and rust, which ultimately leads to the weakening of the steel. When steels rust or sustain holes, they eventually need welding. 

The increase in the use of zinc in coating, plating, or galvanizing domestic materials and even automotive steel parts has continued to generate concerns as to the best way to handle its steel material when damaged and needing welding. 

Welding, of course, can be costly. Thus, preventive measures are always taken to prevent moisture, oxidation, rust, and frequent welding. The material used in order to avoid such damage in steel is zinc. It is used to coat, galvanize and plate steel carbons to allow for durability, prevent moisture, rust, and oxidation.

Although steels are plated, coated, or galvanized with zinc, situations occur which may still lead to damage and the need for welding galvanized steel. Such conditions include accidents or the need to join two or more plated steels. 

Since zinc plated steel is coated by a protective zinc layer, and both are of different materials, it becomes necessary to ask if zinc plated steel can be welded. 

This question leads us to enquire and verify the properties of the two irons, how they differ and how they react when exposed to different degrees of temperature.

The answers to these questions are pathways to the safety measures and requirements against the risk which the possible differences in reaction between zinc and steel under varied temperatures may cause.

Differences Between Zinc And Steel

Of course, zinc and steel differ in many ways, ranging from their chemical compositions to their physical properties and behavior.

In this guide, however, what concerns more is how the differences in chemical compositions may or may not pose safety danger under higher expositions to different degrees in temperature, which welding requires.

Zinc has a lower boiling temperature than steel. Zinc melts at a temperature of 420°c and boils at 709°c. In comparison, steel melts at a temperature of 1400°c. It means that a higher temperature is needed to be able to weld steel than zinc. Supplying the necessary heat to weld steel means that the zinc plate material will not only be first dissolved but vapourize.

This is precisely where the danger lies in welding zinc plated steel. At the level of this zinc vapourization, two dangerous things happen.

 First, at vapourization, zinc releases a dangerous toxic gas or fume, which is capable of causing some respiratory complications. 

Secondly, vaporized zinc can also settle or be trapped in the steel, leading to bubbles inside the weld. This equally leads to the weakening of the welded material, making it fragile.

Worthy of discussion also are the methods of welding zinc plated steel and the step-by-step approach to it. Before that, however, let us look at the safety measures that should guide the welding process.

Safety Measures And Solutions In Welding Zinc Plated Steel

Following the identification of the dangers and impediments associated with welding zinc plated steel, the next focus should be how to overcome these obstacles. In order to accomplish this, it is necessary to observe specific safety measures and techniques that will assist the welder in getting rid of the dangerous zinc plating material. These include:

• Always wear a strong respiratory mask before welding zinc-plated steel.
• The workshop must be adequately ventilated, and the workers made to know the danger of zinc vapor.
• Use lower temperature materials that will not overheat and vapourize the zinc layers. Such low-temperature weld materials include oxy-acetylene fuel, zinc filler rods, and TIG machines.
• Look out for accessible welding techniques which will drastically minimize porosity through speed regulation. 
• A potent alternative to evading the dangerous vapor of heated zinc is to manually find a means to grind or scrape the zinc within the welding area before going on with welding your steel.
• It is also highly advisable that the steel parts be welded before the zinc plating, not the other way around.
• Use local exhaust ventilation (LEV) if you are bent on welding zinc plated steel.
• Hydraulic acid pickle can manually remove the zinc coating from the entire portion before welding zinc plated steel.

Welding Methods For Zinc-Plated Steel

There are different methods of welding zinc plated steel. These methods are briefly highlighted below.

The Manual Method

Under the manual method, the welder first scraps the zinc plates before beginning to weld. This method ensures that the zinc vapor is not emitted with the use of excess heat or temperature. This method can be dangerous too. Thus, the welder is advised to use hand gloves and cover up their faces.

Vaporization Method 

Here, the welder is prepared to hit or supply excessive temperature so that the zinc plate evaporates by itself. The welder is also advised to cover up with both face or nose masks and goggles to prevent the inhalation of the zinc vapor. This method is advisable to be used where there is enough ventilation.

The Carbon Arc Welding Process

This is one of the most widely used methods for welding zinc galvanized steel. The source of heat here is the twin carbon touch. The Arc is directed on the filler rod to melt and produce sufficient heat, but not sufficient enough to destroy the zinc coating.

This technique is primarily used in the sheet metal ductwork industry. This method is advantageous because it requires less zinc to be refilled, replated, and re-galvanized.

The Gas Tungsten Arc Welding

This method is almost the opposite of the carbon arc welding method. It is a slower welding process and leads to the depletion and destruction of larger zinc in the welded steel. Constant redressing of the electrode due to its contamination by the volatilized zinc is very common here. The slower the speed, the more moderate the temperature, but the more destruction the zinc plating witnesses because of its lower boiling and melting points.

Step-By-Step Guide To Welding Zinc Plated Steel

Perhaps, the last thing to acquaint oneself with welding zinc plated steel is the chronological procedures to achieving that job successfully and without accident or damage. These step-by-step guides are better divided into three stages. This is because different welders may employ other orders or steps. Nonetheless, they fall into three phases:

1. Safety readiness
2. Welding
3. Zinc replacement

In the safety readiness stage, the welder has to prepare the workshop and the workers and alert them to the danger of zinc vapor. If the welder decides to use the manual method of scraping the zinc before welding, the appropriate materials, including hand gloves and nose masks, have to be used. There have to be preparations for ventilations also.

The welding stage is the real work proper. Of course, if the welder is using the vaporization method, appropriate measures have to be taken to ensure safety.

The replacement stage has to do with replacing the lost or scraped zinc on the surface of the steel. The replacement of the zinc is to prevent the steel from oxidation, moisture, and rust.

Bottom line: Can You Weld Zinc Plated Steel?

As long as the metal to be used or joined are of the same parent stock, then the answer to the question of whether one can weld zinc plated steel is yes. 

However, strict precautions have to be taken in order to be able to mitigate the danger and health hazards involved.

 Zinc gives off a dangerous metal fume that causes metal fume fever, whose acute symptoms are usually similar to flu and other respiratory organs.