An interview with the Technical Team

Whether you hot dip galvanize steel regularly or are considering it for the first time, choosing the right partner is essential to achieving consistent, high-quality results.

Stuart Cobourne, Group Head of Operations, explains how he and his team work across our nine UK galvanizing plants to help deliver high-quality, sustainable galvanizing.

Can you give us an overview of the department?

My role as Group Head of Operations is to ensure our customers receive products that are not only high quality, but consistently produced, efficient to process, and aligned with modern sustainability expectations. We achieve this by combining strong process control and quality assurance, a clear focus on ESG and our path to net zero, and continuous process improvement to drive operational excellence. This integrated approach allows us to deliver reliable, high-performance products while minimising environmental impact.

We also support our customers beyond general galvanizing services, working collaboratively on product design, material chemistry, and process considerations.

How does Joseph Ash take pride in the quality of their galvanizing?

We take great pride in the extensive work that myself, the department, and colleagues with a technical aspect to their role have completed to refine the chemistry and metallurgy of our processes and deliver a high standard of coating finish.

The Operations team has recently expanded to include a Chemical Engineer and a Process Engineer, and the business in continually growing and developing to stay ahead in the industry and deliver only the best service for our customers.

Why is quality important when looking for a galvanizer?

Industry standards

BS EN ISO1461 states a certain level of product quality must be achieved for general hot dip batch galvanizing to be supplied to the marketplace. The coating must be continuous, with no bare areas that would corrode if not repaired. It must also be relatively smooth, with no sharp edges or zinc build-up that could cause harm or prevent the article from being installed or used. The coating must also be above the specified minimum mean coating thicknesses detailed within the standard.

Installation and use

Steel articles that come for galvanizing are products. The design is critical for ensuring these products are suitable to install and use by our customers and end clients. If the galvanizing process is not considered at the design stage, a product could be returned with zinc build-up on critical faces (i.e. plates that are bolted together), meaning the product cannot be installed. Hole tolerances/threaded components also may not be usable after galvanizing. A product may have to be suspended a certain way through the process, leading to holes being required on visible faces which reduces the aesthetic appeal of the product.

How does the quality of the galvanized finish impact the steel’s lifespan?

If the galvanizer is consulted early on in a product’s design phase, the product can be designed suitably based on considerations regarding steel composition and condition. If the galvanizer pays particular attention to their process chemistry and bath metallurgy then hot dip galvanizing can last, maintenance free, for decades. In some cases, it can last for over a century.

Where these considerations are not given – for example, if the galvanizer skips or rushes stages of the process; or doesn’t operate within parameters – there will be areas on uncoated or under-coated steel. These areas will corrode prematurely, resulting in additional maintenance. In worse cases, articles may need to be disassembled to be reprocessed or replaced. This becomes an expensive and time-consuming task for the customer. That’s why it’s important to make sure your galvanizer understands the important of good quality control and is equipped and able to deliver this.

How does Joseph Ash maintain high standards for quality and stay ahead in the industry?

Joseph Ash operate a high level of factory production control. All stages of the chemical pre-treatment are analysed fortnightly – and the bath metallurgy analysed monthly – using chemical titration and optical emission spectrometry. These processes are then adjusted accordingly to remain within optimum parameters at all times. On top of this, the business operates a Quality Management System certified to ISO 9001 to ensure our quality aspects and impacts are assessed and controlled accordingly.

The business is a member of the UK Galvanizers’ Association and I myself sit on the Technical Committee. This allows us to keep abreast of any upcoming industry risks and have input into standards development. We not only have high standards in the Technical arena but also Health & Safety and Environmental considerations. We are certified to both ISO 45001 and ISO 14001 to manage all of our business risk and impacts, both internally to our colleagues and externally to customers, contractors and the local communities we operate in.

What should customers be aware of when looking to galvanize their steel?

Steel composition

It’s important to ensure that the steel supplied is suitable for galvanizing. When specifying or sourcing steel for fabrications, the steel supplier should be made aware that the steel will be galvanized and supply accordingly. This should be plain carbon, low alloy steels. Where high strength, hardened/cold-worked or high alloy steels are specified, the galvanizer must be consulted at the design stage to ensure any potential concerns can be addressed at the earliest possible stage.

Steel condition

The pre-treatment stage of the galvanizing process involves thorough cleaning of the steel to remove light oils/greases, rust and scale. This allows the characteristic coating growth synonymous with hot dip galvanizing. Whilst robust, this cleaning process cannot remove all potential contaminants that can be present on fabricated steelwork. Paints, wax crayon, labels and weld anti-spatter that is not water-soluble are examples of products that will not be removed by normal processing. Where these products are used, they should be ground off prior to sending material for galvanizing to prevent uncoated areas during the process.

Another common problem can be laser or flame cut edges. The heat-affected zone created by these processes has a dissimilar chemistry to that of the main body of steelwork which can create a very thin (unreactive) coating with poor adhesion. These areas should also be ground prior to sending material for galvanizing.

Design

The steel’s design should also be considered. This includes:

Dimensions – Can the material fit in the bath? Will it need to be double-dipped?
Weight – Is the work too heavy for cranes or FLTs?
Venting and drainage – Have sufficient venting and drain holes been placed? Can the steel be dipped safely, with all internal areas suitably vented to allow air to escape and process chemicals and zinc to drain?
How will the work be suspended by the cranes – are there suitable lifting points for the lifting equipment?
Section size – No part of the fabrication should be more than 2.5x the thickness of any other, as this can cause distortion as the heat transfer of these sections will be different.

We have a venting tips and tricks poster to help our customers with designing their steel for galvanizing.