VW_60250_2010_12_Englisch 大众高强度螺栓

High-Strength Bolts and Screws and Similar Threaded Parts Technical Supply Specifications

Previous issues

VW 60250: 1986-05, 1992-06, 1992-11, 1993-06, 1994-11, 2002-06Changes

The following changes have been made compared with VW 60250: 2002-06:–Technical responsibility changed

–Contents of VDA 235-204: 2009-11 incorporated in all requirements and supplemented

–Information supplemented compared to VDA 235-204: 2009-11 is written in italics in order to

improve recognizability

–Surface flaws restricted as compared to DIN EN 26157-3–Chemical composition (Table 2) changed –Standard completely revised Scope

This standard applies to fasteners and similar threaded parts with external threads made of carbon steel and alloyed steel with a tensile strength range between (1 040 and 1 370) MPa . It contains

requirements for materials and mechanical properties as a supplement to DIN EN ISO 898-1 as well as requirements for manufacturing processes which aim to improve process reliability and to avoid brittle fracture, in particular hydrogen-induced stress crack corrosion.

1

Group Standard

VW 60250

Issue 2010-12

Class. No.:61100

Descriptors:

bolt, screw, property class, list of suppliers, brittle fracture, stress crack corrosion, supply specification

Verify that you have the latest issue of the Standard before relying on it.

This electronically generated Standard is authentic and valid without signature.

The English translation is believed to be accurate. In case of discrepancies, the German version is alone authoritative and controlling.

Page 1 of 6

Confidential. All rights reserved. No part of this document may be provided to third parties or reproduced without the prior consent of the Standards Department of a Volkswagen Group member.

This Standard is available to contracting parties solely via the B2B supplier platform https://www.360docs.net/doc/8318901277.html,.

? Volkswagen Aktiengesellschaft

VWNORM-2010-08e

Description

Drawing specifications

–Example for fasteners of property class 10.9 similar to DIN EN ISO 898-1:

VW 60250 – 10.9

–

Example for fasteners quenched and tempered to a certain strength deviating from DIN EN ISO 898-1 according to drawing specification:

VW 60250 – 115

The strength is indicated by 1/10 of the minimum tensile strength value, in this case "115" for a tensile strength of R m = (1 150 + 150) MPa.

Marking of fasteners

The fasteners must be marked with the appropriate strength code (e.g., 10.9 or 115) and the manu‐facturer's code.

Requirements Mechanical properties

In principle, the mechanical properties of fasteners as set forth in DIN EN ISO 898-1 apply. Fasteners with the property classes 10.9 and 12.9 must furthermore exhibit the following properties deviating from or supplementing the above mentioned DIN standard (see Table 1).

Table 1 – Mechanical and technological properties of fasteners with property classes 10.9

and 12.9

a)

A strength range of +150 MPa and a minimum yield point of 0,9 × R m min apply on principle to all property classes other than 10.9 and

12.9 (see Section 2.1).

b) A conversion of hardness values into tensile strength values, e.g., according to DIN EN ISO 18265, is not permissible.

Chemical composition

The ladle analysis (% weight) according to Table 2 is binding for property class 12.9.

2 2.1 2.2

3 3.1

3.2 Page 2

VW 60250: 2010-12

Table 2

C Si Mn P

S

Al B Cr, Mo, Ni,

V 0,30 to 0,45Max. 0,15

Max. 0,9

Max. 0,02Max. 0,015

0,02 to 0,05

Max. 0,005

Σ ≥ 0,9

Heat treatment

Fasteners according to this standard must be dephosphated prior to heat treatment. Post-quenching

and -tempering of phosphated fasteners is impermissible if the phosphate coating has been applied for reasons of corrosion protection and/or to obtain a given coefficient of friction.

Austenitizing must take place in a controlled furnace atmosphere that is matched to the carbon con‐tent of the material, or in a protective atmosphere. Heat treatment is not permissible on systems that

are used for case hardening and/or carbonitriding.

It must be ensured that, in the hardened state before tempering, the materials of the fasteners have a martensite proportion of at least 90% in the core microstructure of the threaded part.DIN EN ISO 898-1 applies to the re-tempering test.

Permissible suppliers

Fasteners according to this standard must only be manufactured by authorized suppliers. The current list of suppliers must be requested from the respective Procurement Department.

δ-Ferrite

Where subjected to tensile stresses, the surface must not exhibit a metallographically detectable layer enriched with phosphorus (δ-ferrite border).State of carburization

For the property class 12.9, the minimum height of the non-decarburized thread zone is 7/8 H1 (H1:thread depth of the thread, see DIN EN ISO 898-1).Surface flaws

DIN EN 26157-3 applies to permissible surface flaws within the context of qualitative and quantitative evaluation of the fasteners after forming and thread manufacture.

Deviating from DIN EN 26157-3, pickling marks or surface flaws with a depth h ≤ 0,01 × d (d = nominal thread diameter) are permissible in the head-to-shank transition and on the head bearing surface.For larger nominal thread diameters, the depth must not exceed 0,1 mm.

Surface treatment

For high-strength fasteners with tensile strength values R m ≥ 1 040 MPa (320 HV), both the surface treatment and the heat treatment (tempering) processes must always represent the state of the art.This is to avoid hydrogen-induced brittle fractures (please refer to VW 13750 for further information).Fasteners with zinc flake coatings must always be cleaned mechanically or by alkaline treatment. If the parts have to be cleaned chemically (pickling) due to functional reasons (e.g., combined parts,

3.3

3.4 3.5

3.6

3.7

3.8

Page 3

VW 60250: 2010-12

parts with internal threads, rack-plated goods, etc.), only acids with suitable inhibitors must be used for pre-treatment/cleaning.

In order to avoid hydrogen-induced brittle fractures, the surface coatings of fasteners with tensile strength values Rm ≥ 1 040 MPa must not be removed by means of electrochemical processes.Coefficients of friction / installation characteristics

The coefficients of friction occurring when tightening a threaded joint are mostly dependent on the respective conditions of application. The limits of the coefficients of friction are set forth in

VW 01129.

Testing and acceptance

First samples must be delivered together with a first-sample test report according to the applicable QA management agreements for supply parts (Formula Q-Konkret).

The material report must contain the results based on specific tests of the delivery batch at least for the following characteristics:–tensile strength and/or hardness,

–state of carburization, checking for δ-ferrite,–metallographic evaluation of the microstructure,–surface hardness/edge hardness in HV0,3,

–ladle analysis (test report 2.2 acc. to DIN EN 10204),–tempering temperature ,

–information regarding surface treatment (layer thickness, corrosion test report including sam‐ples/images),

–

measurement report (dimensional stability).

Further properties to be tested must be agreed upon between Volkswagen and the manufacturer.The number of parts to be supplied is indicated by the tester of the first sample. They also specify additional test characteristics if necessary.

Each change made to relevant manufacturing methods entails an associated sampling process.Validation of process quality at the manufacturer

The following requirements apply to process validation at the manufacturer:Heat treatment

–Actual manufacturing process: dephosphating directly prior to heat treatment

–Heat treatment at the manufacturer′s facilities or at suppliers released via process audits of the manufacturer

–Process-controlled quenching and tempering facilities: annealing ovens with controlled atmo‐sphere

–Controlled feed

–

Process monitoring of the following characteristics: hardness/tensile strength, oven tempera‐ture , and atmosphere (carbon level)

3.9

4

5

5.1 Page 4

VW 60250: 2010-12

–Metallographic inspections

–Failure-response strategy in case of facility failures

Laboratory

The laboratory must possess the following testing facilities in order to allow manufacturing processes of fasteners to be monitored in a qualified manner:

–complete equipment required for: metallographic testing, hardness and tear testing, proof that

parts are free of phosphate, layer thickness measuring device, test bed for determining the co‐efficient of friction,

–qualified laboratory personnel (e.g. material testers),–failure-response strategy and stand-in regulation.

The use of external laboratory facilities must be agreed upon between Volkswagen and the manu‐facturer.

Surface treatment

–Surface treatment at the manufacturer′s facilities or at suppliers released via process audits of the manufacturer

–Pickling pre-treatment only using acids with suitable inhibitors, specifications for max. pickling duration and concentration

–Tempering after/during electroplating treatments of surfaces (see Section 3.8) - qualified lubri‐cant treatment, if required

–

The specified ranges of the coefficient of friction as well as the corrosion resistance must be ensured

Characteristics for which documentation is mandatory

The following characteristics must be documented for reasons of process validation:–Dimensions /(comparison between desired/actual) and additional requirements as per drawing (e.g., absence of cracks), if required –Tensile strength and/or hardness –

Metallographic evaluation:–Structure

–State of carburization –δ-ferrite

–Parameters of the oven′s atmosphere

–Ladle analysis (test report 2.2 acc. to DIN EN 10204)–Tempering temperature

–Parameters of the coating process

–

Surface flaws and other characteristics rated as critical by the supplier .

Special characteristics for fasteners acc. to VDA Volume 1 "Documentation and Archiving" are spec‐ified in coordination between Volkswagen and the manufacturer. If special characteristics are re‐quired, a product drawing und/or a master data list (SDL, German abbreviation) is to be referenced.

5.2

5.3 6

Page 5

VW 60250: 2010-12

Archiving period

The archiving period for the documents mentioned in Section 6 is to be agreed upon between the manufacturer and Volkswagen.Other applicable documents

The following documents cited in this Standard are necessary to its application.

Some of the cited documents are translations from the German original. The translations of German terms in such documents may differ from those used in this Standard, resulting in terminological inconsistency.

Standards whose titles are given in German may be available only in German. Editions in other languages may be available from the institution issuing the standard.VW 01129Limit Values for Coefficients of Friction; Mechanical Fasteners with Metric ISO Threads

VW 13750Surface Protection of Metal Parts; Surface Protection Types, Codes DIN EN 10204Metallic products - Types of inspection documents

DIN EN 26157-3Fasteners; surface discontinuities; bolts, screws and studs subject to spe‐cial requirements

DIN EN ISO 18265Metallic materials - Conversion of hardness values

DIN EN ISO 898-1

Mechanical properties of fasteners made of carbon steel and alloy steel -Part 1: Bolts, screws and studs with specified property classes - Coarse thread and fine pitch thread

7 8

Page 6

VW 60250: 2010-12