Specification Aluminium Die-Casting Alloy, high silicon content Aluminium Die-Casting Alloy, high silicon content

Transcription

1 Specification Class: Aluminium and Al-alloys Class No.:21 Aluminium Die-Casting Alloy, high silicon content JED 853 Previous Edition Part name (for databases) Aluminium Die-Casting Alloy, high silicon content Scope This specification deals with B390.0 aluminium pressure die casting alloy for the manufacture of connecting rods. This alloy has low corrosion resistance and is only suited for parts which are not exposed to outdoor atmosphere. They are suitable for angled castings. 2 General requirements The finished parts shall be homogeneous and free from pores, blisters and other defects. The surface must be free from remaining mould-material and unevenness. The microstructure shall be an irregular aluminium-silicon eutectic matrix. It shall consist of a uniform distribution of intermetallic phases of silicon in a matrix of aluminium solid solution. The parts must not show any defects such as cracks, voids etc. within their structure. The silicon depletion layer shall be 0.40mm maximum depth on contact surfaces when measured perpendicular to the surface. The requirements for finished parts can be taken from the drawing and the special part specification. The finished part must be pressure tight as specified on the drawing. All materials, even ingredients in small quantities (e. g. cadmium) which are detrimental to health or to the environment are banned from being used unless contained as an alloying element. Corrosion prevention, when required, shall be either a non-hexavalent chromate coating (JED-259) or an anodic oxidation coating (JED-007) to make the part resistant to corrosion and wear. The ingot chosen must meet the specifications as defined by the Release of Suppliers document. If the national material standards establish narrower limits for the properties of the material than those defined in the material specified in the Release of Suppliers, the supplied material must correspond to these narrower limits. 3 Thermal range of application Continuous operational temperature range: -60 C to +260 C For the thermal range of application of the finished parts the range of application of a possibly applied surface coating has to be taken into consideration. Compiler Approved Product Group: 4961 Continuation page 2 to 7 Steve Wolverton Subramaniam Shanmugham Katarzyna Śpiewak JED.dot Template version 03 Hans Voß Doc. Code Language Rev en - C

2 JED-853 : Page 2 4 Properties (Reference NADCA Product Specification for die Casting 2009, Alloy B390.0) 4.1 Mechanical properties The following properties are taken from a separately cast test specimens (i.e. as shown in figure 13 of ASTM B557M) Tensile Strength 260 to 310 MPa Yield Strength > 193 MPa Elongation at Break < 1 % Brinell Hardness 105 to 150 HBW (use 10mm ball with 500 kg weight) (Location maybe specified on drawing) 4.2 Chemical composition (%) Silicon (Si) 16.0 to 18.0 Copper (Cu) 4.0 to 5.0 Manganese (Mn) max Magnesium (Mg) 0.45 to 0.65 Iron (Fe) max Nickel (Ni) max Titanium (Ti) max Zinc (Zn) max Calcium (Ca) max Sodium (Na) max Phosphorus (P) min Others (each) max Others (total) max Aluminium (Al) remainder Sludge Factor (Fe % + 2Mn % + 3Cr %) = 1.80 max. 4.3 Microstructure Phosphorus shall be added as an inoculant by either the ingot producer or the caster to refine the primary silicon phases. The percent phosphorus (80 ppm minimum) is secondary to the solidification rate in achieving the required microstructure as defined in the general requirements Primary silicon particle acceptance levels The graphical representation of the primary silicon particles is shown in the following figures. Primary silicon particle size analysis shall be done by metallographic examination at 100x magnification. The majority of the primary silicon particle size shall not be more than 64 µm. Three particles per square mm between 64 µm and 100 µm are acceptable and one particle per square mm between 100 µm and 135 µm is acceptable. No particles larger than 135 µm are acceptable. Grouped particles with no defined boundary between the particles shall be counted as one particle.

3 JED-853 : Page 3 Uniform distribution TYPE -I

4 JED-853 : Page 4 Uniform distribution TYPE - II

5 JED-853 : Page 5 Non-uniform distribution TYPE III

6 JED-853 : Page 6 Non-uniform distribution TYPE IV From the above graphical representation, Type I and Type II distribution of primary silicon particle is acceptable and Type III and Type IV forms are not acceptable. In addition to this the number of particles shall be min 108 per square millimeter at 100X magnification.

7 JED-853 : Page Examples of microstructure Acceptable Not Acceptable 4.4 Porosity The porosity requirements are defined in the drawing. 4.5 Further properties Very good castability, very good strength retention at elevated temperatures, excellent wear resistance, only conditional weldability, and good suitability for mechanical polishing. 5 Conditions of delivery The material and the finished parts must correspond to the technical conditions of delivery defined in JED Reference Documents ASTM B557M test Methods for Tension testing Wrought and Cast Aluminium and Magnesium Alloy Product NADCA Product Specification for Die Casting 2009 ASTM E716 Sampling Practices for Sampling and Sample Preparation of Aluminium and Aluminium Alloys for Determination of Chemical Composition by Spectrochemical Analysis