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  4. ISO 898-3 Specification

ISO 898-3 Washers

ISO 898-3 Specification 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.
NOTE 1 : These types of washers can also be used with other fasteners such as screws forming their own mating thread.
Washers that conform to the requirements of ISO 898-3 are evaluated at an ambient temperature range of 10 °C to 35 °C. They might not retain the specified mechanical and physical properties at elevated temperatures and/or lower temperatures.
NOTE 2 : Washers conforming to the requirements of this document are used in applications ranging from −50 °C to +150 °C. Users are advised to consult an experienced fastener expert for temperatures outside this range and up to a maximum temperature of +300 °C when determining appropriate choices, or for critical applications.

    ISO 898-3 is applicable to the following flat captive and non-captive washers made of carbon steel or alloy steel, with thickness from 0,2 mm to 12 mm:
  • plain washers (with or without knurls, ribs or chamfers);
  • square washers;
  • square hole washers;
  • shaped plates.
    It does not specify requirements for the following properties:
  • corrosion resistance;
  • weldability.

Related Specifications of ISO 898-3 Washers

ISO 898-1 ISO 898-2 ISO 898-5

ISO 898-3 Chemical Composition

Property class Material and process Chemical composition limits (cast analysis, %) a,b,c Minimum tempering temperature b,c °C
Material Process C P max. S max. B d max.
min. max.
100HV Steel Hot/cold rolled Material selection shall be at the manufacturer's discretion, provided that the requirements of are fulfilled. NA
200HV e Steel Hot/cold rolled or quenched and tempered Material selection shall be at the manufacturer's discretion, provided that the requirements of are fulfilled. NA
300HV f Carbon steel g Quenched and tempered 0.17 0.8 0.035 0.035 0.003 425
Alloy steel h 0.14 1.3 0.035 0.035 0.003 425
380HV f,i Carbon steel g Quenched and tempered 0.4 0.8 0.035 0.035 0.003 425
Alloy steelh 0.2 1.3 0.035 0.035 0.003 380
  • 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 and physical properties

Property class 100HV 200HV 300HV 380HV a
Vickers hardness, HV min. 100 200 300 380
max. 200 b 300 370 450
Rockwell hardness, HRC min. - - 30 39
max. - - 39 45
Partial decarburization, HV 0,3 max. - - c 30 d
Depth of the complete decarburization, G max. - - c 2 % of t eff or 0,02 mm e
Carburization, HV 0,3 max. - - c 30 f
Reduction of hardness after retem- pering, HV 10 max. - - 20 20
  • 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.
  • 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.

ISO 898-3 Hardness

Property class For routine inspection In case of dispute
100HV Bearing surface Bearing surface
200HV a
300HV Hardness in the transverse section
380HV
  • a When washers of property class 200HV are quenched and tempered at the request of the customer at the time of the order, hardness in the transverse section is the reference test in case of dispute.

ISO 898-3 Bolting Surface Treatment Specifications

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ISO 898-3 Bolting Components Marking

Product Shall be Marked with our manufacturing trade mark "TorqBolt" or "TB" along with the designated Grade.
Grade and manufacturer’s identification symbols shall be applied to one end of studs and to the heads of bolts and screws of all sizes. (If the available area is inadequate, the grade symbol may be marked on one end and the manufacturer’s identification symbol marked on the other end.) For bolts and screws smaller than 1⁄4 in. [6 mm] in diameter and studs smaller than 3⁄8 in. [10 mm] in diameter and for 1⁄4 in. [6 mm] in diameter studs requiring more than a total of three symbols, the marking shall be a matter of agreement between the purchaser and the manufacturer.

ISO 898-3 Bolting Certifications

  • EN 10204 3.1
  • EN 10204 3.2
  • PED 2014/68/EC
  • MERKBLATT AD 2000 W2/W7/W10
  • API 20 E BSL 1/ BSL 2
  • NACE MR 0175
  • NACE MR 0103