NF EN 20898-2

La présente norme fixe les caractéristiques mécaniques des écrous en acier au carbone et en acier allié. Elle définit les classes de qualité, marquages, programmes d'essais et méthodes d'essais.

<p>This part of ISO 898 specifies mechanical and physical properties of nuts with coarse thread and fine pitch</p> <p>thread made of carbon steel and alloy steel when tested at an ambient temperature range of 10 °C to 35 °C.</p> <p>Nuts conforming to the requirements of this part of ISO 898 are evaluated at that ambient temperature range.</p> <p>It is possible that they do not retain the specified mechanical and physical properties at elevated and/or lower</p> <p>temperatures.</p> <p>NOTE 1 Nuts conforming to the requirements of this part of ISO 898 have been used in applications</p> <p>ranging from ?50 °C to +150 °C. It is the responsibility of users to consult an experienced fastener materials expert</p> <p>for temperatures outside the range of ?50 °C to +150 °C and up to a maximum temperature of +300°C to determine</p> <p>appropriate choices for a given application.</p> <p>NOTE 2 Information for the selection and application of steels for use at lower and elevated temperatures is given for</p> <p>instance in EN 10269, ASTM F2281 and in ASTM A320/A320M.</p> <p>This part of ISO 898 is applicable to nuts:</p> <p>a) made of carbon steel or alloy steel;</p> <p>b) with coarse thread M5 ≤ <i>D </i>≤ M39, and fine pitch thread M8×1 ≤ <i>D </i>≤ M39×3;</p> <p>c) with triangular ISO metric thread according to ISO 68-1;</p> <p>d) with diameter/pitch combinations according to ISO 261 and ISO 262;</p> <p>e) with specified property classes, including proof load;</p> <p>f) with different nut styles: thin nuts, regular nuts and high nuts;</p> <p>g) with minimum height <i>m </i>≥ 0,45<i>D</i>;</p> <p>h) with a minimum outside diameter or width across flats <i>s </i>≥ 1,45<i>D </i>(see Annex A);</p> <p>i) able to mate with bolts, screws and studs with property classes according to ISO 898-1.</p> <p>For hot dip galvanized nuts, see ISO 10684.</p> <p>This part of ISO 898 does not specify requirements for properties such as:</p> <p>— prevailing torque properties (see ISO 2320);</p> <p>— torque/clamp force properties (see ISO 16047 for test method);</p> <p>— weldability;</p> <p>— corrosion resistance.</p>