Aluminium knowledge

ALUMINIUM KNOWLEDGE

Aluminum alloys (or aluminum alloys; see spelling differences) are alloys in which aluminum (Al) is the predominant metal. The typical alloying elements are copper, magnesium, manganese, silicon, tin and zinc. There are two principal classifications, namely casting alloys and wrought alloys, both of which are further subdivided into the categories heat- treatable and non-heat-treatable. have been very important in aerospace manufacturing since the introduction of metal-skinned aircraft. Aluminum-magnesium alloys are both lighter than other aluminum alloys and much less flammable than other alloys that contain a very high percentage of magnesium
Aluminum_Ingot

WROUGHT ALLOYS

The International Alloy Designation System is the most widely accepted naming scheme for wrought alloys. Each alloy is given a four-digit number, where the first digit indicates the major alloying elements, the second — if different from 0— indicates a variation of the alloy, and the third and fourth digits identify the specific alloy in the series. For example ,in alloy 3105, the number 3 indicates the alloy is in the manganese series, 1 indicates the first modification of alloy 3005, and finally 05 identifies it in the 3000 series

TEMPER DESIGNATION

The temper designation follows the cast or wrought designation number with a dash, a letter, and potentially a one to three digit number, e.g. 6061-T6. The definitions for the tempers are:

  • F : As fabricated
  • H : Strain hardened (cold worked) with or without thermal treatment
  • H1 : Strain hardened without thermal treatment
  • H2 : Strain hardened and partially annealed
  • H3 : Strain hardened and stabilized by low temperature heating

Second digit : A second digit denotes the degree of hardness

  • HX2 = 1/4 hard
  • HX4 = 1/2 hard
  • HX6 = 3/4 hard
  • HX8 = full hard
  • HX9 = extra hard
  • O : Full soft (annealed)
  • T : Heat treated to produce stable tempers
  • T1 : Cooled from hot working and naturally aged (at room temperature)
  • T2 : Cooled from hot working, cold-worked, and naturally aged
  • T3 : Solution heat treated and cold worked
  • T4 : Solution heat treated and naturally aged
  • T5 : Cooled from hot working and artificially aged (at elevated temperature)
  • T51 : Stress relieved by stretching
  • T510 : No further straightening after stretching
  • T511 : Minor straightening after stretching
  • T52 : Stress relieved by thermal treatment
  • T6 : Solution heat treated and artificially aged
  • T7 : Solution heat treated and stabilized
  • T8 : Solution heat treated, cold worked, and artificially aged
  • T9 : Solution heat treated, artificially aged, and cold worked
  • T10 : Cooled from hot working, cold-worked, and artificially aged
  • W : Solution heat treated only

ALLOY DESIGNATIONS

  • 1000 series are essentially pure aluminium with a minimum 99% aluminium content by weight and can be work
    hardened.
  • 2000 series are alloyed with copper, can be precipitation hardened to strengths comparable to steel. Formerly
    referred to as duralumin, they were once the most common aerospace alloys, but were susceptible to stress corrosion
    cracking and are increasingly replaced by 7000 series in new designs.
  • 3000 series are alloyed with manganese, and can be work hardened.
  • 4000 series are alloyed with silicon. Variations of aluminium-silicon alloys intended for casting (and therefore not
    included in 4000 series) are also known as silumin.
  • 5000 series are alloyed with magnesium, and offer superb corrosion resistance, making them suitable for marine
    applications. Also, 5083 alloy has the highest strength of not heat-treated alloys. Most 5000 series alloys include
    manganese as well.
  • 6000 series are alloyed with magnesium and silicon. They are easy to machine, are weldable, and can be
    precipitation hardened, but not to the high strengths that 2000 and 7000 can reach. 6061 alloy is one of the most
    commonly used general-purpose aluminium alloys.
  • 7000 series are alloyed with zinc, and can be precipitation hardened to the highest strengths of any aluminium alloy
    (ultimate tensile strength up to 700 MPa for the 7068 alloy). Most 7000 series alloys include magnesium and copper
    as well.
  • 8000 series are alloyed with other elements which are not covered by other series. Aluminium-lithium alloys are an
    example.

APPLICATIONS

Aerospace alloys

The following aluminum alloys are commonly used in aircraft and other aerospace structures

  • 1420
  • 2004; 2014; 2017; 2020; 2024; 2080; 2090; 2091; 2095; 2219; 2224; 2324; 2519; 2524
  • 4047
  • 6013; 6061; 6063; 6113; 6951;
  • 7010; 7049; 7050; 7055; 7068; 7075; 7079; 7093; 7150; 7178; 7475;
  • 8009;

The following list of aluminum alloys are currently produced, but less widely used

  • 2090 aluminium
  • 2124 aluminium
  • 2324 aluminium
  • 6013 aluminium
  • 7050 aluminium
  • 7055 aluminium
  • 7150 aluminium
  • 7475 aluminium

Second digit : A second digit denotes the degree of hardness

  • HX2 = 1/4 hard
  • HX4 = 1/2 hard
  • HX6 = 3/4 hard
  • HX8 = full hard
  • HX9 = extra hard
  • O : Full soft (annealed)
  • T : Heat treated to produce stable tempers
  • T1 : Cooled from hot working and naturally aged (at room temperature)
  • T2 : Cooled from hot working, cold-worked, and naturally aged
  • T3 : Solution heat treated and cold worked
  • T4 : Solution heat treated and naturally aged
  • T5 : Cooled from hot working and artificially aged (at elevated temperature)
  • T51 : Stress relieved by stretching
  • T510 : No further straightening after stretching
  • T511 : Minor straightening after stretching
  • T52 : Stress relieved by thermal treatment
  • T6 : Solution heat treated and artificially aged
  • T7 : Solution heat treated and stabilized
  • T8 : Solution heat treated, cold worked, and artificially aged
  • T9 : Solution heat treated, artificially aged, and cold worked
  • T10 : Cooled from hot working, cold-worked, and artificially aged
  • W : Solution heat treated only

Marine alloys

These alloys are used for boat building and shipbuilding, and other marine and salt-water sensitive shore applications

  • 5052 aluminium alloy
  • 5059 aluminium alloy
  • 5083 aluminium alloy
  • 5086 aluminium alloy
  • 6061 aluminium alloy
  • 6063 aluminium alloy

Automotive alloys

6111 aluminum and 2008 aluminum alloy are extensively used for external automotive body panels, with 5083 and 5754 used for inner body panels. Bonnets have been manufactured from 2036, 6016, and 6111 alloys. Truck and trailer body panels have used 5456 aluminum. Automobile frames often use 5182 aluminum or 5754 aluminum formed sheets, 6061 or 6063 extrusions.Wheels have been cast from A356.0 aluminum or formed 5xxx sheet. Cylinder blocks and crankcases are often cast made of aluminum alloys. The most popular aluminum alloys used for cylinder blocks are A356, 319 and to a minor extend 242.

Note: Above information are extracted from Wikipedia®