Material Information


Information on the metals used for core plugs:

(CR4 Zinc Plated) Mild Steel BS1449


Mild steel is a ferrous metal made from iron and carbon. It is a low-priced material with properties that are suitable for most general engineering applications. Low carbon mild steel has good magnetic properties due to its high iron content, it is therefore defined as being ‘ferromagnetic’.

Mild steel has a carbon content of between 0.16% and 0.29 % maximum with a relatively high melting point of between 1450°C to 1520°C. Steels with a higher carbon content than mild steel, have a lower melting temperature. This high melting temperature means that mild steel is more ductile when heated, making it particularly suitable for forging, cutting, drilling, welding and is easy to fabricate. Mild steel, including galvanised products, is recyclable.

Mild steel does not have a high resistance to corrosion in its untreated form, however, the corrosion resistance can be greatly improved by applying an appropriate surface protection product to the exposed parts of any project. There is a wide range of red oxide primers, metal paint, metal spray paint and zinc treatments available to enhance the appearance of mild steel and to protect it from rust and corrosion.

Mild steel can be cleaned by ‘pickling’. This is a chemical surface treatment that removes stains, contaminants, rust and scale. Surface rust can also be removed by mechanical grinding and then treating with a surface protector such as red oxide primer, zinc primer and metal paints and sprays. Mild steel is graded according to its chemical composition, how it is produced, and its properties, so you can easily choose the best product for your project.

(Most plugs are zinc plated)


403 Stainless Steel BS EN 10088 3


This grade is a Cr steel hardened by heat treatment, which will attain high mechanical properties after heat treatment. It has good impact strength, corrosion and scaling resistance up to 1200 F (649 C). Applications are steam and gas turbine blades and buckets, bushings, valve components, fasteners, missile rocket components and medical instruments.



CZ108 Brass (63% Copper & 37% Zinc)

Classified predominantly as an alpha brass, CZ108 is a popular material grade due to its hot and cold working properties. It is a high purity cold forming brass and is used where severe bending properties are required. The material can be machined but only at slow speed with very light feeds.




Cup Core Plug - Click Here for removal & installation

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Welch / Dish Type - Click Here for removal & installation

engine core plug
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