Section 5 Steel Castings
A. Liquid Quenched and Tempered
Steel Castings
食品安全手抄报图片1. Scope
The Rules are applicable to statical and centrifugal castings made of liquid quenched and tempered cast steel grades intended for the construction of naval ships and floating equipment.
2. Grades of liquid quenched and tempered
steel castings
Liquid quenched and tempered steel casting grades are quenched and tempered steels alloyed with nickel, chromium and molybdenum, the carbon content of which is so adjusted that, on the one hand, a marten-sitic-bainitic structure is produced on hardening in water or oil, ensuring high strength at the same time as very high toughness and, on the other hand, impair-ment of the component quality during hardening is reliably prevented. Liquid quenched and tempered steel casting grades in the n of the Rules in-clude, for example:
– the GL quality grades GL-M550G, GL-M650G and GL-M700G
– G14NiCrMo10-6 (1.6779) and G17NiCrMo13-6
(1.6781) as per SEW 520
– G15NiCrMo10-6 as per WL 1.6786
G16NiCrMo12-6 as per WL 1.6787
G12NiMoCr17-4 as per WL 1.6788 – HY80 and HY100 as per MIL-S-23008
– G17NiCrMo13-6 as per EN 10213-3
In each ca, the grades or others approved by GL must meet the requirements t out in 3.
3. Technical
requirements
爬楼梯减肥吗3.1 Steel-making
process
The steels shall be manufactured in works approved by GL using the AOD, VOD or VODC process, or using another process approved by GL.
3.2 Chemical
composition
The chemical composition shall satisfy the require-ments stated in the approved specification and in Table 5.1.
In addition, the maximum content of named elements must not exceed the values given in Table 5.2.
3.3 Heat
treatment
The castings shall be subjected to annealing with a transformation of the primary structure and to quench-ing and tempering, in accordance with the data given in the approved specifications or as pe
r Table 5.3. The details of the heat treatment shall be determined by the manufacturer. All individual steps of the heat treat-ment process must be documented.
Table 5.1 Chemical composition of liquid quenched and tempered cast steel grades
Table 5.2 Maximum content of other elements in steel castings
Table 5.3 Data for heat treatment
Table 5.4 Mechanical and technological properties
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3.4 Mechanical
properties
The requirements applicable to the mechanical proper-ties and the impact energy shall conform to the data given in Table 5.4 or to the recognized standards or approved specifications.
教英语的英文3.5 External and internal condition Depending on the quality requirements, the external and internal condition shall conform to the verity levels as per Chapter 2, Section 4, G.
For the test, the castings can be subdivided into testing zones with different requirements regarding their quality levels. The subdivision is bad on one or more of the following principles:
– operating loads to be expected
– effect of defects on the component safety
– possible risk of damage on failure of the com-ponent
– required welding reliability at the interctions
– necessary freedom from defects after machining If the evaluation is carried out according to other stan-dards, the requirements shall be equivalent to tho specified in the GL Rules.
If castings are required to undergo final inspection in accordance with the AD data sheets, proof of the qual-ity levels and scopes of testing shall be furnished in accordance with the Rules.
3.5.1 Severity
levels
For the admissibility of external and internal imperfec-tions in castings, the provisions t out in Chapter 2, Section 4, G.3. apply.
3.5.2 Surface
finish
易简理发器The surface finish of the castings must permit the execution and evaluation of the prescribed non-destructive tests.
In the areas that are not machined, the castings must be freed from their casting skin completely – as far as is technically possible - by grinding. The surface qual-ity to be achieved thereby should comply with refer-
ence sample 4 S 2 of Technical Recommendation No. 359-01 1. In the area of the welding edges, the surface quality must comply with reference sample 2 S 2. The welding edges shall be stated in the casting drawing. The width of the welding edges shall be 1,5 × the wall thickness.
4. Testing
The castings shall be prented for testing in the fin-ished condition (delivery condition) and shall undergo the following tests. In the ca of castings intended for steam boilers, Chapter 2, Section 4, D.1.2 shall be obrved. Casting of safety class I shall be tested indi-vidually.
4.1 Tensile
testing
The mechanical properties shall be verified by tensile testing. The tests shall be performed on a heat-by-heat basis, parts undergoing the same heat treatment being grouped into test batches in accordance with Chapter 2, Section 4, A.10.2.2. A tensile test specimen shall be taken from each test batch and tested. Cast-ings with unit weights > 1000 kg shall be tested indi-vidually.
4.2 Notched-bar impact bending test
小白船歌词完整版
The castings shall be subjected to the notched bar impact test. The number of ts of test specimens (3 Charpy V-notch specimens per t) shall be deter-mined in the same way as the number of tensile test specimens.
4.3 Hardness
test
All quenched and tempered steel castings which are tested on a heat-by-heat basis shall be subjected to a comparative hardness test. The result of the hardness test shall show that quenching and tempering has been carried out homogeneously (the difference in hardness between the hardest and the softest tested component in the test batch shall not exceed 30 HB).
4.4 Non-destructive
testing
The manufacturer shall ensure by non-destructive tests on his products that the requirements pertaining to the external and internal condition according to 3.5 are met. Unless otherwi agreed, the scope of testing shall conform to TRD 103 or AD data sheet W5, whichever is appropriate. Valve
s and fittings are sub-ject to TRD 110. Furthermore, the Rules t out in Chapter 2, Section 4, A.10.4 shall be obrved.
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1Bureau de Normalisation des Industries de la Fonderie, France B. Non-Magnetizable Steel Castings
1. Scope
The Rules are applicable to steel castings made of non-magnetizable steels which are ud for the con-struction of naval vesls and floating equipment.
白羊座双鱼座2. Suitable grades of casting
The following, or comparable, grades of casting with a relative permeability µr < 1,01 may be ud, provided that they meet the requirements of 6.:
– non-magnetizable casting steel as per SEW 395 – other non-magnetizable casting steels conform-ing to other standards or specifications, after
their suitability has been established by GL. An
initial test of product suitability on the manufac-
turer's premis may be required for this pur-
po.
–the non-magnetizable cast steel grades accord-ing to Table 5.5
Table 5.5 Materials for non-magnetizable steel
castings in accordance with WL
3. Selection of the grades of cast steel
Non-magnetizable casting steels which are intended for cargo-handling and processing equipment with design temperatures below 0 °C, or for which a special chemical stability in relation to the cargo or operating fluids is required, must additionally comply with the requirements for castings t out in Chapter 2, Section 4, E. “Steel Castings for U at Low Temperatures” and F. “Stainless Steel Castings”.
4. Heat treatment and delivery condition
All steel castings shall be supplied in a heat-treated condition appropriate to the grade of cast steel, i.e. they must be solution-annealed and quenched in water.
5. External and internal condition
5.1 Basic
requirements
Depending on the quality requirements, the external and internal condition shall conform to the quality levels as per Chapter 2, Section 4, G.
For testing of internal condition there should be ud the radiographic inspection. In view to ultrasonic inspection special agreements have to be met.
For the test, the castings can be subdivided into testing zones with different requirements regarding their quality levels. The subdivision is bad on one or more of the following principles:
– operating loads to be expected
– effect of defects on the component safety
– possible risk of damage on failure of the com-ponent
– required welding reliability at the interctions
– necessary freedom from defects after machining
If the evaluation is carried out according to other stan-dards, the requirements shall be equivalent to tho specified in Chapter 2, Section 4, G.
If castings are required to undergo final inspection in accordance with the AD data sheets, proof of the qual-ity levels and scopes of testing shall be furnished in accordance with the Rules.
5.2 Severity
levels
For the admissibility of external and internal imperfec-tions in castings, the provisions t out in Chapter 2, Section 4, G.3. apply.
5.3 Surface
finish
The surface finish of the castings must permit the execution and evaluation of the prescribed non-destructive tests.
In the areas that are not machined, the castings must be freed of their casting skin completely - as far as is technically possible - by grinding.
6. Requirements applicable to the material 6.1 Chemical
composition
The limits stated in the standards and/or the specifica-tions approved by GL are applicable.
6.2 Resistance to intercrystalline corrosion
All grades of cast steel shall be resistant to intercrys-talline corrosion in the condition in which they are supplied. If it is intended to weld castings without post-weld heat treatment, only grades of cast steel that are corrosion-resistant in this condition shall be ud, e.g. cast steels stabilized with Nb or containing not more than 0,03 % C. Becau of the alloy content, no demands can be made on the steel grades 1.3802 and 1.3966 with regard to their resistance against intercrystalline corrosion; the test shall be omitted for the steels.
6.3 Mechanical properties and impact energy The requirements specified in the standards or in the approved specifications are applicable.
7. Testing
The castings shall be prented for testing in the fin-ished condition (delivery condition) and shall undergo the following tests:
7.1 Tensile
testing
The mechanical properties shall be verified by tensile testing. The tests shall be performed on a heat-by-heat basis, parts undergoing the same heat treatment being grouped into test batches in accordance with Chap-ter 2, Section 4, A.10.2.2. A tensile test specimen shall be taken from each test batch and tested. Castings with unit weights > 1000 kg shall be tested individu-ally.
7.2 Notched-bar impact bending test
The castings shall be subjected to the notched bar impact bending test. The number of ts of test speci-mens (3 Charpy V-notch specimens per t) shall be determined in the same way as the number of tensile test specimens.
7.3 Test of resistance to intercrystalline
corrosion
The manufacturer shall check the resistance to inter-crystalline corrosion of austenitic steel castings in-tended for welded asmblies and – where stipulated in the order – of other austenitic steels as well. Testing shall be carried out in the following conditions:
– steels containing C ≤0,03 % and stabilized steels: after nsitizing heat treatment (700 °C,
30 minutes, quenching in water)
– all other steels: in the condition in which they are supplied. At least two specimens from each
heat shall be tested in accordance with
ISO 3651-2. The test shall be confirmed by the
manufacturer by means of a certificate.
7.4 Non-destructive
testing
The manufacturer shall ensure by non-destructive tests on his products that the requirements pertaining to the external and internal condition according to A.3.5 are met. Unless otherwi agreed, the scope of testing节约用水小短文
shall conform to AD Data Sheet W5; valves and fit-tings are subject to TRD 110. Furthermore, the R
ules t out in Chapter 2, Section 4, A.10. shall be ob-rved.
7.5 Testing the permeability
For castings of non-magnetizable steel, the relative permeability µr shall be determined by random tests on a metallic clean surface for the delivery condition. For the number of necessary random samples e Table 5.6.
The relative permeability µr must not exceed the value of 1,01. Table 5.6 Number of random samples
