ASME B18.8.2-2020 pdf download

ASME B18.8.2-2020 pdf download.Taper Pins,Dowel Pins,Straight Pins, Grooved Pins, and Spring Pins(lnch Series).
4.5 MateriaL and Heat Treatment
4.5.1 SteeL. hardened ground machine dowel pins shall be made from any carbon or alloy steel capable of being heat treated to a core hardness of Rockwell C50 minimum and having sulfur and phosphorus content not in excess of 0.05% and 0.04%, respectively.
4.5.2 Heat Treatment. Pins shall be hardened by quenching in oil from the austenizing temperature and tempering to meet the following conditions.
4.5.2.1 Case-Hardened Pins. Pins shall he case hardened to a mini in u in total case depth of 0.0 1 0 in. for noniinal iin sizes ‘32 Iii., 01 smaller, and 0.015 in. for nominal pin sizes 6 iii., and larger. The case shall have a mini mu in surface hardness of Rockwell C70, oi equivalent, and the core hardness shall he Rockwell C47 to C58. The microstructure shall be tempered marten- site.
4.5.2.2 Through-Hardened Pins. At manufacturer’s option, pins smaller than A/H in. nominal size may he through hardened to a hardness of Rockwell C50 to C58. However, in no instance shall the hardness of the pin surface he softer than that of the core. The microstruc— tu re shall be tempered martensite.
4.6 Finishes
unless otherwise specified, machine dowel pins shall be furnished with a ground (as processed) finish or with black oxide coating at the option of the manufacturer. A lightweight oil in ay be used to in hi hit co ri-os i oii dun tig transportation. Other protective or decorative finishes, where required, shall be subject to agreement between the manufacturer and purchaser. however, where a finish applied to carbon or alloy steel pins is such that it might produce hydrogen embrittlement, the pins shall be baked for a suitable time at a temperature that will obviate such embrittlement. Baking shall be accomplished as soon as possible following the plating or coating operation inasmuch as delay is detrimental to achieving the desired results. Where additive-type finishes are used, the tabulated dimensions and tolerances shall apply to the pins prior to application of the plating or coating, unless otherwise specified by the purchaser.
4.7 Workmanship
Dowel pins shall he free from detrimental burrs, cracks, seams, or nicks and other defects affecting their serviceal)ility or properties.
4.8 Designation
4.8.1 Hardened ground machine dowel pins shall be designated L)y the following data, in the sequence shown:
product name (noun first), including pin series; nominal pin diameter (fraction or decimal equivalent); length (fraction or decimal equivalent); material; and protective finish, ii required. Sec examples below.
EXAM P1 ES:
(1) Pin, hardened Ground Machine Dowel — Standard Series, :4 1 ‘/, Steel, Phosphate Coated
(2) Pin, Hardened Ground Machine Dowel — Oversize Series, O.625() x 2.SO0, Steel
4.9 AppLication Information
4.9.1 HoLe Sizes. Because of the wide variety of materials in which (lowel pins are uSe(I and of the many design requirements which must be considered, it is not possible to provide hole size recommendations that will be suitable for all applications. However, the suggested hole sizes in Table 4.9.1- 1 have been commonly used for press—fitting standard series machine dowel pins into material such as mild steels and cast iron. In soft materials such as aluminum or zinc die castings, hole size limits are usually decreased by 0.0005 in. to increase the press fit.
Holes for oversize series machine dowel pins may L)est he determined by the user to suit the particular application
4.9.2 Design CaLcuLations. For design calculations, the shear strength of these standard pins should he based on the values listed in para. 4.9.1.
4.9.3 ResponsibiLity for Modification. The manufacturer shall not be held responsible for product malfunctions that are due to plating or other modifications when such plating or modification is not accomplished undertheir control or direction.
4.9.4 Installation Warning. Pins should not beinstalled by striking or hammering and, when installingwith a press, a shield should be used and safety glassesworn.