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What is BS EN 1561 - Founding grey cast irons about?
This European standard deals with the classification of grey cast irons that are specified by their tensile strength or hardness. BS EN 1561:2023 is a revised standard that incorporates significant technical changes and updates.
Who is BS EN 1561 - Founding grey cast irons for?
- CEOs and technical directors of foundries and melt shop managers
- Quality assurance managers and technicians
- Foundry engineers
- Laboratory and test house managers involved in the testing and quality assurance of grey cast components
- Designers and engineers involved in specifying and designing components in grey cast iron
- Purchasing managers involved in specifying and purchasing components in grey cast iron
What does BS EN 1561 - Founding grey cast irons cover?
BS EN 1561 specifies the properties of unalloyed and low-alloyed grey cast irons used for castings, which have been manufactured in sand moulds or in moulds with comparable thermal behaviour.
It specifies the characterizing properties of grey cast irons by either:
- The tensile strength of cast samples, or
- The hardness measured on the castings or on a cast-on knob
If agreed by the manufacturer and the purchaser, the combination of both tensile strength from option a) and hardness from option b) may be specified.
BS EN 1561 specifies six grades of grey cast iron by a classification based on tensile strength measured on machined test pieces prepared from cast samples and six grades of grey cast iron by a classification based on Brinell hardness.
NOTE: BS EN 1561 does not cover technical delivery conditions for iron castings; see BS EN 1559-1 [3] and BS EN 1559-3 [4]. It does not apply to grey cast irons used for pipes and fittings according to BS EN 877 [5].
Why should you use BS EN 1561 - Founding grey cast irons?
- It’s useful. The specification of material grades according to their mechanical properties is relevant for most EN-GJL material orders. The standard also specifies material grades according to maximum hardness for e.g. wear resistance.
- The use of uniform test methods and specified material grades can result in cost savings for manufacturers.
- It enables precision: specified mechanical properties can be reached with high statistical security, especially by SME foundries producing castings in the wall thickness range mostly affected by the revision.
- Grey cast iron is a very cost-efficient cast iron-based material, with some particularly beneficial characteristics such as ease of manufacture and machining, and good thermal and damping properties.
- It benefits the environment as the raw material for grey iron castings is scrap iron and steel derived from parts at end of life. Supporting the further use of grey cast iron will avoid additional energy use and save resources.
- The standard can help user organizations grow sustainably, improve their efficiency and increase confidence along the supply chain
What’s new about BS EN 1561 - Founding grey cast irons?
This is a revision of BS EN 1561:2011, which was undertaken because of application problems between foundries and their customers. The basic table specifying minimum mechanical properties is revised. Additional significant technical changes in BS EN 1561 include:
- An explanation is added regarding the combination of relevant wall thickness and tensile strength in cast samples and in the casting itself
- A better description is given of the different types of sampling
- Data are given for up to seven ranges of relevant wall thickness
- Required minimum tensile strength to be obtained in cast sample is decreased for relevant wall thickness > 50 mm and subdivided
- Material grade EN-GJL-350 is a niche grade used for limited applications only so is removed. (It can still be manufactured upon agreement on specific properties between the customer and the manufacturer.)
- Mandatory Brinell hardness values are given for up to seven ranges of relevant wall thickness, considering section sensitivity
- A short description is added on the use of the different sample types. All types are allowed, but some types have certain advantages or restrictions to be pointed out to the customer.
- Size and type of required cast sample in relation to relevant wall thickness is introduced
- An informative annex is added for the comparison of grey cast iron material designations according to BS EN 1560 and ISO/TR 15931
- Examples are inserted to explain the relationship between wall thickness and mechanical properties
- The anticipated values of tensile strength in casting are decreased for relevant wall thickness > 50 mm and subdivided
