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Conditions

Below is an explanation of the basic states in which the various aluminium alloys can be found, depending on the post-processing to which they are subjected during their transformation.

DENOMINATION OF THE BASIC STATES OF THE PROCESS

F: Manufacturing rough | Applied to the manufacturing process of semi-products in which there are no special controls over the thermal conditions or cold deformation used. There are no values established for the mechanical properties.

O: Annealing | Applied to semi-products to obtain the lowest state of resistance.

H: Work-hardening (Usually stretching/rolling) | Applied to semi-products whose strength has increased by cold deformation, with or without intermediate heat treatment to achieve reduction of the mechanical properties.

W: Solution heat treatment and quenching | This is a state applied only to alloys that spontaneously mature at room temperature after solution treatment and quenching. This state will only be used when the natural maturing time is indicated. For example W 1/2 hour.

T: Structural hardening heat treatment | For semi-products in which their mechanical strength is increased by heat treatment, with or without additional work hardening, to obtain stable states.

SUB-DIVISIONS OF THE BASIC STATES OF TREATMENT OF ALUMINIUM

1. STATE H SUB_DIVISION: WORK HARDENING

1.1_ The first figure that follows the H indicates the specific variation of the basic operations of the process according to:

H1: Work hardening only | The mechanical properties are achieved by a final process of cold deformation.

H2: Work hardening and partial annealing | The mechanical properties are obtained by a final heat treatment. In general, this state has a greater extension than a H1 with the same strength.

H3: Work hardening and stabilising | Applied to semi-products that are hardened by cold plastic deformation and whose mechanical properties have subsequently been stabilised by heat treatment at low temperature. Stabilising generally decreases mechanical strength and increases ductility. This denomination is only applicable to alloys that undergo softening at room temperature if not stabilised, such as those of AlMg.

1.2_ The digit that follows the denominations H1, H2 and H3 refers to the mechanical properties of the semi-finished product:

HX2: 1/4 hard state | Its tensile strength is approximately halfway between that of the annealed state and that of the semi-hard state.

HX4: Semi-hard state | Its tensile strength is approximately halfway between that of the annealed state and that of the hard state.

HX6: 3/4 hard state | Its tensile strength is approximately halfway between that of the semi-hard state and that of the hard state.

HX8: Hard state | This has the highest level of work hardening generally used.

HX9: Extra-hard state | Its tensile strength exceeds that of the hard state. The odd digits will indicate states whose tensile strength is the average of those corresponding to the states of adjacent even-numbered digits.

1.3_Third digit (x) in the sub-division of state H. The three digits following the letter H are used for all forgeable alloys:

H (x)11: | Applied to semi-products that after final annealing maintain hardening by cold deformation that prevents classifying them as annealed state (0), but is not enough to classify them as H(x)1. Example: The hardening achieved by controlled traction straightening is called H111 (extension of approximately 1%).

H 112: | Applied to semi-products that may acquire some hardening by deformation at high temperature and for which there are some limits to the mechanical properties.

H 113: | Applied to plates which, after final annealing maintain hardening by cold deformation that prevents classifying them as annealed state (0), but is not enough to classify them as H(x)1 (extension of approximately 3%).

2. SUB-DIVISION OF T STATES: HEAT TREATMENT

1.1_The figures from 1 to 10 that follow the letter "T" indicate the specific sequences of the basic treatments, as can be seen below.

T1: Quenching treatment from the extrusion and natural maturation temperature | Applied to semi-products which, from the extrusion temperature, receive cooling at sufficient speed (quenching), so that with subsequent natural maturation, their mechanical properties increase. Included in this state are products which, after cooling, are subjected to flattening or straightening by traction without any significant effects on the mechanical properties.

T2: Quenching treatment from the extrusion, work hardening and natural maturation temperature | Applied to semi-products which, after cooling at sufficient speed (quenching) from the extrusion (or rolling) temperature, receive specific work hardening followed by natural maturation in order to improve their mechanical strength. Included in this state are products which, after quenching, are subjected to flattening or straightening by traction with effects on the mechanical properties.

T3: Solution heat treatment (1), quenching (1), work hardening and natural maturation | Applied to semi-products which, after solution treatment or quenching, receive specific work hardening followed by natural maturation in order to improve their mechanical strength. Included in this state are products which, after quenching, are subjected to flattening or straightening by traction with effect on their mechanical properties.

T4: Solution heat treatment (1), quenching (1), and natural maturation | Applied to semi-products that improve their mechanical properties after solution treatment, quenching and natural maturation. Included in this state are products which, after quenching, are subjected to flattening or straightening by traction without effects on the mechanical properties.

T5: Quenching heat treatment from the extrusion and artificial maturation temperature | Applied to semi-products which, from the extrusion temperature, receive cooling with forced air at sufficient speed (quenching), so that with subsequent artificial maturation, their mechanical properties increase. Included in this state are products which, after cooling, are subjected to flattening or straightening by traction without any significant effects on the mechanical properties.

T6: Solution heat treatment (1), quenching (1), and artificial maturation | Applied to semi-products that improve their mechanical properties after solution treatment, sudden quenching and artificial maturation. Included in this state are products which, after quenching, are subjected to flattening or straightening by traction without effects on the mechanical properties.

T7: Solution heat treatment (1), quenching (1) and over-maturation/stabilising | Applied to semi-products that are artificially matured after solution treatment and quenching, beyond the limit corresponding to the maximum strength in order to control some significant property.

T8: Solution heat treatment (1), quenching (1), work hardening and artificial maturation | Applied to semi-products that receive specific work hardening between quenching and artificial maturation to improve their strength. Included in this state are products which, after quenching, are subjected to flattening or straightening by traction with effects on the mechanical properties.

T9: Solution heat treatment (1), quenching (1), artificial maturation and work hardening | Applied to semi-products that are cold deformed after solution treatment, quenching and artificial maturation, to improve their mechanical strength.

T10: Quenching heat treatment from the extrusion temperature, work hardening and artificial maturation | Applied to semi-products that after cooling (quenching) and before artificial maturation receive specific work hardening.

2.1_A second figure added (should not be 0), indicates variations in the treatment that significantly alter the properties of the semi-products. The most significant are the following:

T31: | Solution heat treatment, quenching and 1% work hardening.

T41: | Solution heat treatment and quenching with coolant at temperature.

T35: | Solution heat treatment, quenching and controlled traction from 1.5 to 3%.

T36: | Solution heat treatment quenching and 7% work hardening.

T42: | Solution heat treatment from 0 or F, quenching and natural maturation.

T62: | Solution treatment from 0 or F, quenching and artificial maturation.

T51, T52, T53, T54: | Cooling (quenching) from the extrusion temperature with different levels of cooling, so that different final mechanical properties are achieved with the same artificial maturation.

T53: | Cooling, (quenching), from the extrusion temperature and double artificial maturation.

T61: | Solution heat treatment, quenching and artificial maturation in different conditions from T6.

T72: | Stabilised treatment from T42.

T73: | Solution heat treatment, quenching, and maturation with double treatment (stabilising to improve corrosion resistance under tension and maturation).

T74: | Solution heat treatment, quenching in water at a temperature above 50ºC and maturation with double treatment (Stabilising + Maturation).

T76: | Solution heat treatment, quenching, and maturation with double treatment (Stabilising to improve resistance to exfoliating corrosion + Maturation).

T81: | Solution heat treatment, quenching, hardening by deformation and artificial maturation. Hardening by traction from 1.5% to 3%.

T83: | Similar to T8 for Simagaltok 63/EN AW 6063 alloy.

T86: | Solution heat treatment, quenching, work hardening and artificial maturation. Work hardening usually comes from 6% traction straightening.

T87: | Solution heat treatment, quenching, hardening by deformation and artificial maturation. Work hardening usually comes from 7% traction straightening.

T89: | Solution heat treatment, quenching and sufficient hardening to achieve the mechanical properties and artificial maturation.

T93, T94: | Solution heat treatment, quenching and sufficient hardening to achieve the mechanical properties.

2.2_The third figure added indicates stress elimination by controlled tension straightening, as follows:

T(x)51: | Applied to semi-products which, after solution heat treatment and quenching, indicates the work hardening that they receive from final straightening by controlled traction of 1 to 3% These bars will not be subjected to subsequent straightening

T(x)50: |As for the previous one but applied to bars, profiles, extruded and stretched tubes: Percentage straightened work hardening by controlled traction of 3%, minus the tube from 0.5 to 3%.

T(x)511: | As for the previous one but a smaller stretch is allowed after the controlled traction.