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RECOMMENDATIONS FOR OBTAINING SAMPLES OF CASTING PARTS – MECHANICAL CHARACTERISTICS

15.04.2013

This manual has been put together to clarify the methods that should be used to obtain samples of material (commonly known as specimens), representing the cast parts’ mechanical and metallographic characteristics, whether Grey or Spheroidal casting.

For Pdf version please click here RECOMMENDATIONS FOR OBTAINING SAMPLES OF CASTING PARTS – MECHANICAL CHARACTERISTICS

Table of Contents

1.     INTRODUCTION

2.     TERMS & DEFINITIONS

3.     UNE-EN 1561:2011 “FOUNDING – GREY CAST-IRONS”

4.     UNE-EN 1563:2011 “FOUNDING – SPHEROIDAL GRAPHITE CAST-IRONS” 


 

  1. 1.     INTRODUCTION

This manual has been put together to clarify the methods that should be used to obtain samples of material (commonly known as specimens), representing the cast parts’ mechanical and metallographic characteristics, whether Grey or Spheroidal casting.

The material’s mechanical characteristics can be assessed in machined specimens made from: independent samples, samples attached to the part, samples included in the part and/or samples cut from the part.

Due to the size and type of the parts cast at Fumbarri, whenever a material’s mechanical characteristics are going to be assessed, we recommend you use the samples included in the part, as they are the ones that best represent the parts’ characteristics.

There are currently two standards that set the methodology for defining samples, and these standards are as follows: UNE-EN 1561:2011 “Founding – Grey Cast-irons” and UNE-EN 1563:2011 “Founding – Spheroidal Graphite Cast-irons”.

  1. 2.     TERMS AND DEFINITIONS

–            Casting sample: An amount of cast material that represents the casting material, including independent samples, attached samples and samples included in the part. The specimen to be tested will be obtained from these samples through machining.

–            Independent samples: Sample cast in an independent sand mould under the representative manufacturing conditions and type of material.

–            Sample attached to the part: Sample cast in the mould along with the part, with a common filling system.

–            Sample included in the part: Sample that is directly joined to the casting part. At Fumbarri we recommend this system to obtain samples.

–            Deciding wall thickness: The wall thickness that is representative of the casting parts, and which is defined by determining the size of the casting samples for which the mechanical properties are applied.

  

3.     UNE-EN 1561:2011 “Founding – Grey Cast-irons”

3.1            Tensile and HB hardness characteristics of grey cast-iron, measured in machined specimens using casting samples.

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* For deciding wall thicknesses of t>100mm, the casting types are not classed according to their hardness. As the deciding thickness increases, the hardness decreases. For further details on hardness, please see the UNE-EN 1561:2011 standard “Founding – Grey Cast-irons”.

3.2            Definition of samples for tensile testing

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Figure 1. Type 1 – Sample included in the part:

Upper part TYPE B, lower part TYPE A

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Thickness, For TYPE A ; >50 <=100, for TYPE B ; >100 <=200

3.3            Additional information on the mechanical and physical characteristics of the casting samples with a crude casting diameter of 30 mm.

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3.4            Placing the sample in the part

The sample will be stuck to the model, on the working side, and in a horizontal position (good side). It should never be placed on the bottom of the bases or inside the drawers, or in a vertical position, as the material’s characteristics can be altered by the mould filling process.

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3.5            Errors in samples

For Grey Cast-iron, only the geometry of the previously shown sample should be applied, as otherwise the specimen obtained will not be representative of the material’s characteristics. A common error is to use samples for Spheroidal Cast-iron in Grey Cast-iron.

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OLYMPUS DIGITAL CAMERA

ERROR: Spheroidal casting specimen placed on a Grey casting base.

It is a common error to place samples inside the drawers or in a vertical position. This should be avoided, as the filling process or the residue deposits from the polystyrene combustion are left inside the specimens, making them invalid for the purpose in question, which is to represent the part’s characteristics and its deciding thickness.

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ERROR: Spheroidal casting specimen placed on a Grey casting base, inside a drawer.

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ERROR: Spheroidal casting specimen placed on a Grey casting base, in a vertical position.

 

  1. 4.     UNE-EN 1563:2011 “Founding – Spheroidal Graphite Cast-irons”

4.1            Tensile and HB hardness characteristics of spheroidal cast-iron, measured in machined specimens using casting samples.

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4.2            Definition of samples for tensile testing

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Figure 5. Samples included in the part – Types C & D

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4.3            Additional information about the characteristics of spheroidal casting.

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4.4            Placing the sample in the part

The sample will be stuck to the model, on the working side, and in a horizontal position (good side). It should never be placed on the bottom of the bases or inside the drawers, or in a vertical position, as the material’s characteristics can be altered by the mould filling process.

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4.5            Errors in samples

For Spheroidal Cast-iron, only the geometry of the previously shown sample should be applied, as otherwise the specimen obtained will not be representative of the material’s characteristics.

Never place the samples inside the drawers or in a vertical position, as the residue deposits from the polystyrene combustion would be left in the specimens, altering the material’s characteristics.

Samples stuck to copies or profiles should not be placed, as this would cause hot spots that may lead to contraction defects (shrinkages).

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ERROR: Specimen placed in the part’s vertical position and in the profiling zone.

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ERROR: Specimen placed in a vertical position and inside a drawer.

OLYMPUS DIGITAL CAMERA

ERROR: The sample is not according to standard measurements and is placed in the profiling zone.

OLYMPUS DIGITAL CAMERA

ERROR: The sample is placed in the copy zone.

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ERROR: The sample is placed in the copy zone.

Signed:

Ignacio Martínez Del Agua

Quality Manager

Fundiciones Fumbarri-Durango