En Iso 13920-bf !new!

: This refers to the tolerance class for shape and position (straightness, flatness, and parallelism) . Key Features of ISO 13920 ISO 13920 An Explained Guide to Welding General Tolerances

You would ask for clarification. Likely they want:

A good default recommendation for many industrial fabrications is the balanced combination, which aligns with the BF in this article. en iso 13920-bf

Page 1. Welding — General tolerances for. welded constructions — Dimensions. for lengths and angles, shape and. position. iTeh Standards En Iso 13920 PDF - Scribd

Class B represents standard, everyday workshop accuracy. It is tighter than classes C and D but does not demand the expensive precision of class A. : This refers to the tolerance class for

Even a part that appears perfect at a macro level will reveal imperfections at a micro view. As long as an imperfection will still allow the part to function as designed, that given part does not necessarily have to be scrapped. Dimensional tolerance, or the total amount a specific dimension may vary, is the difference between the upper (maximum) and lower (minimum) limits. Because it is impossible to manufacture everything to an exact size, tolerances are used on production drawings to control part variation and ensure proper assembly. In the world of welding, this concept is governed by the international standard . This article explores the EN ISO 13920 standard in detail, with a particular focus on deciphering the " BF " designation and its practical implications.

The suffix tells the manufacturer exactly which tolerance "bracket" to use for different types of measurements: Page 1

Selecting the right class is an engineering decision based on the part's function and manufacturing cost, as tighter tolerances mean more difficult and expensive production.

Welding involves intense, localized heat. As the molten weld metal cools, it contracts, introducing thermal stress and physical distortion (warping, bowing, and twisting) into the assembly.

These define the allowable variation in the overall length of a welded component. For example, a beam with a nominal length of 1000mm might have a tolerance of roughly ± 2mm or ± 3mm depending on specific sub-sections of Class B. 2. Angularity Tolerances (Class B)