DIN 51350-2-2008 PDF

Full title and description

STB DIN 51350-2-2008 — Testing of lubricants — Testing in the four‑ball tester — Part 2: Determination of welding load of liquid lubricants. This document specifies a test method using the four‑ball (Shell) tester to determine characteristic values (good load and welding load) of liquid lubricants, in particular extreme‑pressure (EP) type lubricants and additives intended to allow high contact pressures in mixed‑film lubrication.

Abstract

This standard defines the apparatus configuration, test specimen preparation, operating parameters (speed, temperature, load application), test sequence and result reporting for measuring the welding (failure) load of liquid lubricants in a four‑ball tester. The method yields repeatable values used to compare EP performance and to screen formulations and additives. The procedure and interpretation align with the DIN 51350 series of four‑ball methods and related international four‑ball test procedures.

General information

• Status: Withdrawn / superseded (the DIN 51350‑2:2008 edition was later covered by subsequent editions in 2010 and ultimately updated in the consolidated DIN 51350‑2:2015 edition).
• Publication date: 01 November 2008 (designation often shown as DIN 51350‑2:2008).
• Publisher: Deutsches Institut für Normung (DIN).
• ICS / categories: 75.100 — Lubricants, industrial oils and related products.
• Edition / version: STB DIN 51350‑2‑2008 (local catalogues and distributors may label the 2008 DIN text with an STB prefix when listing translated/adopted copies).
• Number of pages: ca. 6 pages (short method specification typical for this part of the DIN 51350 series).

Scope

The scope covers determination of welding (seizure) load of lubricants that are liquid at room temperature when tested in the four‑ball tester. It applies to liquid lubricants and additives intended to improve load‑carrying capacity (EP behaviour) and provides instructions for preparing samples, selecting test parameters, conducting the test and reporting welding‑load results for comparative and quality‑control purposes. The method is one part of the DIN 51350 family of four‑ball test procedures.

Key topics and requirements

• Apparatus: four‑ball (Shell) tester configuration, ball materials and dimensions, clamping and heating arrangements.
• Test conditions: specified rotational speed, temperature control, sequence of applied normal loads and dwell times to determine welding load (failure load).
• Specimen and sample handling: sample volume, cleanliness, pre‑conditioning and sample temperature control.
• Measurement and evaluation: definition of welding/seizure event, reporting of welding load and any auxiliary observations (scoring, wear scars, friction if measured).
• Repeatability and comparability: recommendations for number of repeats, reporting format and units to enable comparison across laboratories and formulations.
• Safety and equipment verification: checks and maintenance of the tester, calibration of load and speed, and safe handling of heated samples and high‑load tests.

Typical use and users

Used by lubricant formulators, additive manufacturers, quality‑control and R&D laboratories, independent testing houses and OEMs to screen and compare EP performance and to support product specifications. The short, focused procedure is useful for routine batch control, comparative ranking of formulations and research into anti‑wear/EP additive behaviour.

Related standards

Part of the DIN 51350 series of four‑ball tester methods (other parts address wear characteristics, consistent lubricants and shear stability). Equivalent or related four‑ball and extreme‑pressure test methods include various ASTM four‑ball procedures (for example ASTM D2596, D4172 and D2783), IP and ISO four‑ball methods; ISO/IEC and other national standards describe comparable procedures and the DIN 51350 parts are cross‑referenced in international overviews of four‑ball testing.

Keywords

four‑ball tester, welding load, seizure load, extreme‑pressure (EP), lubricants testing, lubricant additives, DIN 51350, four‑ball method, wear, testing method, lubricant quality control.

FAQ

Q: What is this standard?

A: It is the DIN method (published as DIN 51350‑2:2008 and sometimes listed as STB DIN 51350‑2‑2008 in distribution catalogues) that specifies how to determine the welding (seizure) load of liquid lubricants in a four‑ball (Shell) tester.

Q: What does it cover?

A: The standard covers apparatus configuration, sample preparation, specified test parameters (speed, temperature, load sequence), test execution and result reporting to determine the welding load—a comparative measure of extreme‑pressure performance—for liquid lubricants.

Q: Who typically uses it?

A: Lubricant formulators, additive manufacturers, QC and R&D laboratories, independent test labs and OEMs use the method for formulation development, quality control and comparative screening of EP performance.

Q: Is it current or superseded?

A: The 2008 edition has been superseded by later editions in the DIN document history (documents dated 2010 and a consolidated revision in 2015 are shown as subsequent editions). For current test practice use the latest DIN 51350‑2 edition (check the issuing body, DIN, for the presently valid version).

Q: Is it part of a series?

A: Yes — it is one part of the DIN 51350 family of four‑ball tester methods (other parts address wear of liquid lubricants, testing of consistent lubricants, shear stability etc.), and these parts are commonly cross‑referenced with international four‑ball procedures.

Q: What are the key keywords?

A: Four‑ball tester, welding load, seizure, EP (extreme pressure), liquid lubricants, testing method, DIN 51350.