TRL_22002-002_Rohling_FW_Koerper_2010-09-15_EN-material standard
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Technical Guideline
Material Specification:
Blank Steel for runner blocks
TRL 22002-002
(Steel yield strength higher than 400 N/mm2)
2010-09-15
M aterials and semi-finished products
Replacement for:
SWN 22002-002: 2002-05-07
? B o s c h R e x r o t h A G 2006
Bosch Rexroth Mechatronics GmbH erstellt: S w P /QMM4, G. Haller
E rnst-Sachs-Str. 100 ? 97424 Sch weinfurt geprüft: S w P /QMM4, Dr. S. Frenznick Germany freigegeben: DC-IA/E LT7, Richard Weidner
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Contents
page
1 Purpose ..........................................................................................................................
2 2 Scope .............................................................................................................................2
3 Terms and Abbreviations ...............................................................................................2
4 Responsibilities..............................................................................................................2 5
Material Specifications (2)
5.1 Steel Smelting and Casting Method ...................................................................................2 5.2 Chemical Composition ......................................................................................................2 5.3 Purity Grade (non-metallic inclusions).. (3)
5.4 Magnetization ..................................................................................................................3 6
Heat Treatment and Structure ........................................................................................4 6.1 Heat Treatment ................................................................................................................4 6.2 Microstructure ..................................................................................................................4 6.3 Surface Decarburization ...................................................................................................4 7
Mechanical Properties....................................................................................................4 7.1 Tensile Strength ...............................................................................................................4 7.2 Yield Strength ..................................................................................................................4 7.3 Yield Strength Ratio..........................................................................................................4 7.4 Hardness .........................................................................................................................4 7.5 Machinability (only for machinability optimized steels): ........................................................4 8 Test Certificate ...............................................................................................................5 9 Additional Agreements...................................................................................................5 10
Normative References (5)
1 Purpose
This technical guideline is applicable to blank steel used for the manufacture of runner blocks with steel inserts.
2 Scope
The technical guideline is applicable for Bosch Rexroth Mechatronics GmbH and their subsidiaries and na-tional organizations.
3 Terms and A bbreviations
DC Bosch Rexroth AG
DCL Bosch Rexroth Mechatronics GmbH
DC-IA Bosch Rexroth Industrial Applications
SwP Schweinfurt Plant of the Bosch Rexroth Mechatronics GmbH
DC-IA/ELT7 Entwicklung Lineartechnik Proze?unterstützung
SwP/QMM4 Materials Laboratory
TRL Technische Richtlinie (Technical Guideline), Bosch Rexroth Mechatronics GmbH
4 Responsibilities
Responsible for the content of this technical guideline is SwP/QMM4.
Modifications of this technical guideline are restricted to DC-IA/ELT7.
5 Material Specifications
5.1 Steel Smelting and Casting Method
5.1.1 Quality Requirements
Within the scope of this central standard, the product of the original smelting process is called a heat. In order to ensure unique identification of the finished product, it must be marked such that heat and finished product can be directly associated.
The supplier is responsible for complying with the quality requirements requested, and has to carry out the tests required for ensuring the quality requirements. The appropriate production and test records must be submitted on demand.
5.1.2 Process
The smelting type must be selected such that it ensures utmost purity (low content of non-metal inclusions).
When recycling steel is smelted, it must be ensured that radioactively c ontaminated steel is reliably prevented from being used. The finished product must not show any radioactivity exceeding the natural radioactivity: limit 0.1 Bq/g (Becquerels per gram – specific activity).
Delivery batches must be separated by heats and production orders.
5.1.3 Special Secondary Metallurgy
Ladle metallurgy and type of deoxidation are not specified.
A calcium treatment for adjustment of the sulfur content and influencing the sulfide form as well as for opti-
mizing the machinability is admissible.
5.2 Chemical Composition
The decisive criterion for choosing a material is to meet the criteria, particularly the mechanical properties (point 7).
For good machinability the chromium content could be minimized whereas the sulfur can be maximized with respect to the allowed macroscopic and microscopic inclusion contents.
The following steel grades are specified for use:
?heat-treatable steels according to DIN EN 10083-2 [z. B. C55 (1.0535); C60 (1.0601)]
?bearing steels according to DIN EN ISO 683-17 [z. B. 43CrMo4 (1.3563)]
?Ferritc-pearlitic steels for precipitation hardening
?Calcium-treated steels (for optimizing the machinability) with the following chemical composition (values given in percent by weight):
Beside the steelgrade also each steelworks must be sanctioned with an initial sample by SwP-materials laboratory before delivery.
5.3 Purity Grade (non-metallic inclusions)
5.3.1 Macroscopic Purity
The Steel must be free from metallurgical defects through its cross section (core) and surface bracking defects on all profile forms. If it is not possible to completely prevent macroscopic defects, such as outside and inside cracks, gas inclusions, shrinkage cavities, slag inclusions, doubling, lap seams, powder inclusions or pronounced slag lines etc., the following action must be taken as a 100%-test for checking the purity on a macroscopic scale:
?method I:
Ultrasonic - testing (or comparable non-destructive testing) of the rolling ingot respectively
of the hot-rolled bar.
?method II:
US (ultrasonic) - testing (or comparable non-destructive testing) of the pre-machined roller block at
the critical areas: prism of the steel insert, ball returning means, ―radii of the inner geometries―.
5.3.2 Microscopic Purity
According to DIN 50602, the microscopic purity grade is evaluated as an "overall total index" for oxides (O) and sulfides (S) using Method K. In borderline cases, the test according to DIN 50602 can be r epeated.
The numerical value of the overall total index [K] is a function of the cross-sectional area [A] of the raw profile:
5.4 Magnetization
Magnetization is defined as the vector sum of the atomic magnetic moments in relation to the unit of volume.
It must be ensured that the magnetization of a runner block delivered to DCL is less than 5 A cm-1.
6 Heat Treatment and Structure
6.1 Heat Treatment
The used material shall be heat-treated for the required mechanical properties.
6.2 Microstructure
For ‘heat-treatable steels’ the structure shall be uniform distributed ferrite and pearlite [pearlite min. 50 % l a-minar] or a quenched-and-tempered structure.
Especially for materials corresponding to bearing steels the structure shall be rated and reported in accor-dance with ‘Prüfung nach SEP 1520’ as follows [globular carbides within ferrite]:
?CG [size of carbides] max. 2.4
?PA [amount of perlite] max. 3.1
?CN [carbide network] max. 5.1
?CZ [carbide streaks] max. 6.3/7.4
6.3 Surface Decarburization
The manufacturer must ensure that any surface Decarburization ist removed by a machining process.
7 Mechanical Properties
7.1 Tensile Strength
R m = 650 – 740 N/mm2
Calcium-treated steels for optimizing the machinability: max. 780 N/mm2
7.2 Yield Strength
R p0,2 > R e > 400 N/mm2
7.3 Yield Strength Ratio
Rp0,2/Rm = Re/Rm 0.8
If R p0,2 > 480 N/mm2 and A5 > 15 % then:
R p0,2/R m = R e/R m≤ 0,86
7.4 Hardness
Hardness according to DIN EN ISO 6506-1: 192 – 219 HBW 2,5/187,5
Calcium-treated steels for optimizing the machinability: max. 240 HBW 2,5/187,5
7.5 Machinability (only for machinability optimized steels):
V15 > 375 m min-1
According to ISO 3685
8 Test Certificate
A material test certificate 3.1 (DIN EN 10204) must be submitted for each material batch used. This test certif-
icate must contain the following test results based on a specific test:
?process
?casting
?dimension of the ingot resp. cross-section of the billet
?address of the steel-mill and No. of the heat charge
?sizes and shapes of the rolled bars
?delivery date of the semifinished product to the machining manufacturer
?an alignment of the longitudinal axis of the block relatively to the rolling direction
?identification of the charges
?number of units (per charge) delivered to DCL
?chemical composition
?heat-treatment and structure
?tensile strength (target / actual value)
?yield strength (target / actual value)
?hardness Brinell (target / actual value)
?yield strength ratio R p0,2 / R m (target / actual value)
?purity (target / actual value)
?radioactivity (confirmation in writing)
?identification of the parts
Changes in the material test certificate can be made, but only with written agreement from DCL.
The supplier must still guarantee that he will comply with the default standard.
As regards radioactivity, the supplier of the raw material must submit a confirmation stating that he did not use any contaminated material.
The test certificate must be submitted to the DCL plant or DCL supplier not later than on receipt of the goods.
9 Additional A greements
One or more additional requirements may apply formulated in written form. The corresponding document number of the SwP materials laboratory has to be documented within the test certificate.
10 Normative References
Publication Title
Standards
DIN EN ISO 6506-1 Metallic materials — Brinell hardness test — Part 1:
Test method
DIN EN ISO 643 Steels — Micrographic determination of the apparent grain size
DIN 50602 Microscopic examination of special steels using standard diagrams to assess the
content of non-metallic inclusions
DIN EN 10204 Metallic products – Types of inspection documents
SEP 1520 Microscopic examination of carbide structure in steels by means of diagram
series.