ISO 9587:2007 pdf download – Metallic and other inorganic coatings一 Pretreatment of iron or steel to reduce the risk of hydrogen embrittlement.
Parts made from steel with actual tensile strengths greater than or equal to 1 000 MPa (with corresponding hardness values of 300 NV 10, 303 NB or 31 NRC) and surface-hardened parts shall require heat treatment unless class SR-C Is specified. Preparation Involving cathodic treatments in alkaline or acid solutions shall be avoided.
Tables 1 and 2 list stress-relief heat-treatment classes that can be specified by the purchaser to the electroplater. supplier or processor on the pan drawing or purchase order. When no stress-relief treatment class is specified by the purchaser, then class SR-I shall be applied.
NOTE 1 The treatment class selected is besed upon experience Mm the part or simfar parts, and the specific alloy used, or Mth empincal test data. Sonic pans, because of factors such as alloy composition and structure, size, mass or design parameters. cen perform satisfactorily with no stress-relief treatment. Therefore, Class SR-0 treatment is provided for parts that the purchaser wtshes to exempt from treatment
NOTE 2 The use of inhibitors Ii acid picidlig baths does not necessarily guarantee that hydrogen ernbritllenierit is mirWmzed,
NOTE 3 Class SR-I. the longest treatment, is the default when the purchaser does not specify a class. The electroplaler, supplier or processor is not normally in possession of the necessary information, such as design considerations, induced stresses from mwiufactunng operations, etc. • that have to be considered in selecting the correct stress-relief treatment. It is in the purchaser’s interest that their part designer, nianufacttwing engineer or other technecaly qualified individual specify the treatment class on the part dra*ng or purchase order, m order to avoid the extra cost of the default treatment
5 Categorization of steels
With the exception of surface-hardened parts the heat treatment conditions shall be selected on the basis 04 the actual tensile strength. When only the mmimum tensde strength is specified or it the tensile strength is not known, the heat treatment condition shall be selected by relating known or measured hardness values to equivalent actual tensile strengths. The tensile strength, or equivalent derived from known or measured hardness values, shall be supplied by the purchaser.
Steels that have been wholly or partly surface hardened shall be considered as being in the category appropriate to the hardness of the surface-hardened layer.
6 Stress relief
6.1 For high strength steels, the following conditions apply. For steels of actual tensile strength less than
1 000 MPa, stress-relief treatment is not essenhal. For steels of actual tensile strength greater than or equal to
1 000 MPa, the conditions given in Tables 1 and 2 shall apply. The heat treatment shall be carried out before
commencement of any preparation of cleaning treatment using aqueous solutions, or before any treatment
liable to cause embfltttement.
6.2 Combinations of shorter time at appropriate higher temperatures may be used if they have been shown not to be detnmental. For tempered steels, articles shall not be heated above a temperature that shall be at least 50 °C below the tempenng temperature.
6.3 If stress relief is given after shot-peening in accordance with ISO 12686 or other cold working process to introduce beneficial compressive stresses, the temperature shall not exceed 230 ‘C.
6.4 For articles made & steel with an actual tensile strength below 1 400 MPa, articles having surface- hardened areas that would suffer an unacceptable reduction in hardness by treatment in accordance with Tables 1 and 2 shall be heat treated at a lower temperature, but at not less than 130 C, for a mmwnum penod of 8 h. Lower-temperature heat treatment can adversely affect the fatigue strength of the article.