ISO/TR 4956:1984 pdf free.Wrought steels for use at elevated temperatures in engines.
1.1 This Technical Report covers technical delivery requirements and technical information for wrought steels supplied for parts such as bolts, blades, discs or casings in stationary or non-stationary turbines required to withstand relatively high mechanical Stresses at elevated temperatures (above about 400 °C) and additionally corrosive attack by hot gases.
NOTE — Other steel types exist which are used mainly for large engine parts; these steel types are not covered by this Technical Report, since they are sold mainly to proprietor specifications only.
1.2 Unless otherwise stated, this Technical Report is applicable to blooms, billets, bars, forgings, strip, sheet, plates and wire in the delivery conditions given in 4.2.
1.3 International Standards exist for heat-resisting steels (see ISO 4955)1), valve steels for internal combustion engines (see ISO 683/15), and steels for use on and with pressure vessels and boilers (see ISO 2604/1 to 6).
3 Ordering
3.1 The purchaser shall state in his enquiry and order
a) the steel type (see table 2);
b) the product form and the dimensions and tolerances of the product (see 4.8);
c) the treatment condition including surface condition (see 4.2);
ci) the quantity to be delivered;
e) the requirement class (see table 1);
f) the required type of document (see 5.6).
3.2 Certain options in ordering are permitted by this Technical Report and the purchaser may also state in his equiry and order his
related requirements as shown below.
a) whether a product analysis is required (see 4.4.2);
b) whether the mechanical properties for other dimensions than according to table 4 are to be specified;
c) in cases in which tensile and impact properties are to be verified on reference test pieces and in cases in which more than one heat treatment is indicated in tables 4 and 5 for the type of steel concerned, the heat treatment to be applied (see 5.3.3.3);
4 Requirements
4.1 Manufacture of the steel and of the product
Unless otherwise agreed in the order, the processes used in making the steel and the product are at the manufacturer’s discretion. When he so requests, the user shall be informed what steelmaking process is being used.
4.2 Treatment condition at the time of delivery
4.2.1 The surface and heat-treatment condition at the time of deiivery is to be agreed at the time of enquiry and order.
4.2.2 Products which are not determined for further hot- or cold-forming operations are usually delivered in the heat-treatment conditions indicated in table 5.
Products intended for further forming operations are usually delivered in the following conditions:
a) in the case of martensitic steels: ‘annealed on a hardness <270 HB”;
b) in the case of austenitic steels: “treated for further forming operations”.
4.2.3 The steels are delivered by casts.
4.3 Requirement classes1)
The steels covered by this Technical Report shall be ordered and delivered in accordance with one of the requirement classes given in table 1.ISO/TR 4956:1984 pdf free download.