ISO 898-3 Specification

This document specifies mechanical and physical properties of flat washers, designed to be used in bolted joints in combination with bolts, screws, studs and nuts with a specified property class in accordance with ISO 898‑1 and ISO 898‑2.

ISO 898-3 Chemical Composition

Property class Material and process Chemical composition limits (cast analysis, %)a,b,c Chemical composition limits (cast analysis, %)a,b,c
Material Process C C P S Bd °C
100HV Steel Hot/cold rolled Material selection shall be at the manufacturer’s discretion, provided that the requirements of Table 3 are fulfilled. NA
200HVe Steel Hot/cold rolled or quenched and tempered Material selection shall be at the manufacturer’s discretion, provided that the requirements of Table 3 are fulfilled. NA
300HVf Carbon steel,g Quenched and tempered 0,17 0,80 0,035 0,035 0,003 425
Alloy steel,h 0,14 1,30 0,035 0,035 0,003 425
380HVf,i Carbon steel,g Quenched and tempered 0,40 0,80 0,035 0,035 0,003 425
Alloy steel,h 0,20 1,30 0,035 0,035 0,003 380
Note:

Key
NA = not applicable.
a. In case of dispute, the product analysis applies.
b. For captive washers, see ISO 10644 or ISO 10673. Chemical composition and minimum tempering temperature shall be agreed between the purchaser and the supplier at the time of the order.
c. For special applications (e.g. washers to be hot dip galvanized), chemical composition and minimum tempering temperature shall be agreed between the purchaser and the supplier at the time of the order.
d. Boron content shall be 0,003 % maximum, but it may be up to 0,005 % provided that non-effective boron is controlled by the addition of titanium and/or aluminium.
e. Property class 200HV washers can be manufactured using raw material having the right mechanical property or by quenching and tempering washers after manufacturing. Process choice is at manufacturer’s discretion provided that the requirements of Table 3 are fulfilled.
f. There shall be a sufficient hardenability to ensure a structure consisting of approximately 90 % martensite in the core section in the “as-hardened” condition before tempering.
g. Carbon steel can contain additives, e.g. chromium, manganese, nickel, etc.
h. Alloy steel shall contain at least one of the following elements in the minimum quantity given: chromium 0,30 %, manganese 0,20 %, nickel 0,30 %, vanadium 0,10 %, molybdenum 0,08 % and boron 0,000 8 %. Where elements are specified in combinations, the limit value to be applied for steel class determination is 70 % of the sum of the individual minimum values specified above for the elements concerned.
i. For hydrogen embrittlement consideration, see future ISO/TR 20491.

ISO 898-3 Mechanical properties

Property class   lOOHV ZOOH V 300HV 380H\f3
Vickers hardness, HV min. 100 200 300 380
max. 200b 300 370 450
Rockwell hardness, HRC min. - - 30 39
max.
 -
 -
 39
 45
Partial decarburization, HV 0,3 max. - - c 30d
Depth of the complete decarburization, G max. - - c 2 % of teff or 0,02 mme
Carburization, HV 0,3 max. - - c 30f
Reduction of hardness after retem‑ pering, HV 10 max. - - 20 20
Note:

a. Property class 380HV is currently not included in existing ISO product standards; if required, the use of this property class shall be agreed between the purchaser and the supplier.
b. Exceeding the maximum hardness up to 250 HV shall not be cause of rejection.
c. For knurled or ribbed washers, the limits specified for property class 380HV shall apply.
d. Hardness at 0,1 mm from the bearing surface shall not be more than 30 Vickers units below the measured hardness on a transverse radial section through the washer in accordance with 8.2.3.
e. The lowest value applies.
f. Hardness at 0,1 mm from the bearing surface shall not be more than 30 Vickers units above the measured hardness on a transverse radial section through the washer in accordance with 8.3.