ASME B18.2.6M:2012 pdf free download

ASME B18.2.6M:2012 pdf free download.Metric Fasteners for Use in Structural Applications.
ASME B18.2.6M covers the complete general and dimensional data for products in the metric series recognized as American National Standard for sizes M 12 through M36. These four metric structural products include
(a) metric heavy hex structural bolts: ASTM A325M and ASTM A490M
(b) metric heavy hex nuts: ASTM A563M
(C) metric hardened steel washers; circular, circular clipped, and beveled: ASTM F436M
(d) metric compressible washer-type direct tension indicators: ASTM F959M
1.1.2 The inclusion of dimensional data in this Standard is not intended to imply that all products described herein are stock production sizes. Consumers should consult with suppliers concerning lists of available stock production sizes.
1.2 DImensions
All dimensions in this Standard are in millimeters, unless stated otherwise, and apply to unplated or uncoated product. When plating or coating is specified, the finished product dimensions shall be as agreed upon between supplier and purchaser. Symbols specifying geometric characteristics are in accordance with
ASME Y14.5.
1.3 Options
Options, where specified, shall be at the discretion of the supplier, unless otherwise agreed upon by the purchaser and supplier.
1.4 Terminology
For definitions of terms relating to fastener dimensional or component features used in this Standard, refer to ASME B18.12.
1.5 ComparIson to ISO and CEN Standards
ISO 4775 is similar to the nut in this Standard.
ISO 7415 is similar to the structural washer in this Standard.
There are no comparable ISO standards for compressible indicating washers.
The diameter of chamfer circle on double chamfered nuts and the diameter of washer face shall be within the limits of the maximum width across flats and 95% of the minimum width across flats.
The tops of washer faced nuts shall be flat, and the diameter of the chamfer circle shall be equal to the maximum width across flats with a minus tolerance of 15%. The length of chamfer at hex corners shall be 5% to 15% of the basic thread diameter. The surface of chamfer may be slightly convex or rounded.
Bearing surfaces shall be flat and, unless otherwise specified, shall be perpendicular to the axis of the threaded hole within the total runout (FIM) tabulated for the respective nut size, type, and strength level.
3.1.4 Corner FilL A rounding or lack of fill at junction of hex corners with chamfer shall be permissible. provided the width across corners is within specified limits at and beyond a distance equal to 17.5% of the basic thread diameter from the chamfered faces.
3.1.5 Position of Hexagon to Tapped Hole. At maximum material condition, the nut body shall be located at true position with respect to the thread pitch diameter within a tolerance zone having a diameter equivalent to 4% of the maximum width across the flats.
3.1.6 Countersink. The tapped hole shall be countersunk on the bearing face or faces. The maximum countersink diameter shall he 1.08 times the thread basic (nominal) major diameter. No part of the threaded portion shall project beyond the bearing surface.
3.1.7 Threads. Threads shall be Class 6H in accordance with ASME Bi.13M except when overtapping is ft’luired according to para 3.1.7.2.
3.1.7.1 Thread Gaging. Unlessotherwisespecified by the purchaser, gaging for screw thread dimensional acceptability shall be in accordance with Gaging System 21 as specified in ASME 131.3.
3.1.7.2 Overtapping. When nuts are zinc coated, either hot dip or mechanical, they shall be ocertapped in accordance with the requirements in ASTM A563M.
3.2 Nut Materials
Chemical and mechanical properties of heavy hex nuts shall conform to ASTM A563M property classes.
3.3 Nut Finish
Unless otherwise specified, nuts shall he supplied with a plain (as-processed) finish, unplated or uncoated. II a finish is required, it shall conform with the applicable finish standard listed in ASTM A563M. The finish on nuts shall be the same type as that designated on and approved for the mating bolts.