ISO 898 is an international standard

International standard

International standards are standards developed by international standards organizations. International standards are available for consideration and use, worldwide...

 that defines mechanical and physical properties for metric fasteners

ISO metric screw thread

The ISO metric screw threads are the world-wide most commonly used type of general-purpose screw thread. They were one of the first international standards agreed when the International Organization for Standardization was set up in 1947.-Basic profile:...

. This standard is the origin for other standards that define properties for similar metric fastener

Fastener

A fastener is a hardware device that mechanically joins or affixes two or more objects together.Fasteners can also be used to close a container such as a bag, a box, or an envelope; or they may involve keeping together the sides of an opening of flexible material, attaching a lid to a container,...

s, such as SAE J1199 and ASTM F568M

ASTM F568M

ASTM F568M is an ASTM International standard for metric bolts, screws and studs that are used in general engineering applications. It is officially titled: Standard Specification for Carbon and Alloy Steel Externally Threaded Metric Fasteners...

. It is divided into five (nonconsecutive) parts:

1. Bolts, screws and studs with specified property classes – Coarse thread and fine pitch thread

2. Nuts with specified proof load values – Coarse thread

5. Set screws and similar threaded fasteners not under tensile stresses

6. Nuts with specified proof load values – Fine pitch thread

7. Torsional test and minimum torques for bolts and screws with nominal diameters 1 mm to 10 mm

With exception to part 7, which defines test standards, the parts of this standard define properties for fasteners made of carbon steel and alloy steel. The standards define that the testing must be performed at ambient temperatures, which is defined as between 10 and 35 °C (50 and 95 F). The standards do not cover fasteners that would otherwise apply but require special properties, such as weldability

Weldability

The weldability, also known as joinability, of a material refers to its ability to be welded. Many metals and thermoplastics can be welded, but some are easier to weld than others...

 or corrosion resistance.

Part 1

Part 1 defines the mechanical properties of bolts, screws, and studs

Threaded rod

A threaded rod, also known as a stud, is a relatively long rod that is threaded on both ends; the thread may extend along the complete length of the rod. They are designed to be used in tension...

. It specifically applies to fasteners that have an ISO metric screw thread as defined in ISO 68-1. The properties are defined for M1.6-39 with coarse threads and M8-39 with fine threads. The diameter and pitch combinations must adhere to ISO 261 and ISO 262 and the thread tolerances must adhere to ISO 965

ISO 965

ISO 965 is a International Organization for Standardization standard for metric screw thread tolerances. It specifies the basic profile for ISO general purpose metric screw threads conforming to ISO 261.The tolerance system refers to the basic profile in accordance with ISO 68-1...

 parts 1, 2, and 4.

Part 1 does not specify properties for fasteners that have head geometries that reduce the shear strength

Shear strength

Shear strength in engineering is a term used to describe the strength of a material or component against the type of yield or structural failure where the material or component fails in shear. A shear load is a force that tends to produce a sliding failure on a material along a plane that is...

 of the fastener, such as low head screws and countersunk

Countersink

A countersink is a conical hole cut into a manufactured object, or the cutter used to cut such a hole. A common usage is to allow the head of a countersunk bolt or screw, when placed in the hole, to sit flush with or below the surface of the surrounding material...

 heads. It also excludes set screw

Set screw

A set screw is a type of screw generally used to secure an object within or against another object. The most common examples are securing a pulley or gear to a shaft. Set screws are most often headless , meaning that the screw is fully threaded and has no head projecting past the major diameter of...

s, which are covered under part 5.

Part 2

Part 2 defines the mechanical properties for coarse threaded nuts up to an M39 size and a height of at least half the nominal diameter.

Part 5

Part 5 defines the mechanical properties for set screws and other fasteners not under tensile stresses. It defines properties for sizes M1.6 through M24.

Part 6

Part 6 is the same as part 2 except for fine threaded nuts that range from M8 to M39. Note that the working temperature range for these fasteners is -50 C

Part 7

Part 7 defines how to perform torsional tests on bolts and screws that have a nominal diameter less than or equal to 10 mm. This standard only applies to short screws and bolts with a nominal diameter between 3 and 10 mm.

External links

• Mechanical properties of common ISO property classes