Lloyds LR Type 550 Cast steels

Material group: Ferrous Alloys / Cast steels

Country / Standard: United Kingdom / Lloyds

Data updates

Latest Update: 2024-12

Total number of updates: 1

Update History

This material has 61 properties — only a subset is shown here.

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Lloyds LR Type 550 Chemical Composition

CRITERIA

VALUE

UNIT

CAS NUMBER

CRITERIA

VALUE

0.01 – 0.03

UNIT

CAS NUMBER

7429-90-5

CRITERIA

VALUE

≤ 0.03

UNIT

CAS NUMBER

7440-38-2

CRITERIA

VALUE

≤ 0.20

UNIT

CAS NUMBER

7440-44-0

CRITERIA

VALUE

val1

UNIT

CAS NUMBER

7440-48-4

CRITERIA

VALUE

val1

UNIT

CAS NUMBER

7440-47-3

CRITERIA

VALUE

val1

UNIT

CAS NUMBER

7440-50-8

CRITERIA

VALUE

val1

UNIT

CAS NUMBER

7439-96-5

CRITERIA

VALUE

val1

UNIT

CAS NUMBER

7439-98-7

CRITERIA

VALUE

val1

UNIT

CAS NUMBER

7727-37-9; 17778-88-0

CRITERIA

VALUE

val1

UNIT

CAS NUMBER

7440-02-0

CRITERIA

VALUE

val1

UNIT

CAS NUMBER

7723-14-0

CRITERIA

P+S

VALUE

val1

UNIT

CAS NUMBER

CRITERIA

VALUE

val1

UNIT

CAS NUMBER

7439-92-1

CRITERIA

VALUE

val1

UNIT

CAS NUMBER

7704-34-9

CRITERIA

VALUE

val1

UNIT

CAS NUMBER

7440-36-0

CRITERIA

VALUE

val1

UNIT

CAS NUMBER

7440-21-3

CRITERIA

VALUE

val1

UNIT

CAS NUMBER

7440-31-5

CRITERIA

VALUE

val1

UNIT

CAS NUMBER

7440-32-6

CRITERIA

VALUE

val1

UNIT

CAS NUMBER

7440-62-2

CRITERIA

VALUE

val1

UNIT

CAS NUMBER

7440-67-7

Rules for the Manufacture, Testing and Certification of Materials, Chapter 4 Section 4; Steel Castings; Steel castings for special marine application, Lloyd's Register, 2025

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Lloyds LR Type 550 Physical Properties

Temperature

0 - 30°C

PROPERTY / VALUE

Modulus of Elasticity

190 — 210 GPa

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Density

7.67 — 7.86 kg/dm³

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Poisson Coefficient

0.27 — 0.3

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This material has 61 properties — only a subset is shown here.

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Lloyds LR Type 550 Heat Treatments

The castings are to be supplied in the quenched and tempered heat treatment condition. The castings are to be subjected, as necessary, to an appropriate refining treatment before being heated for water quenching or spray quenching and tempering. The manufacturer is to determine the detailed heat treatment to produce castings to meet the requirements of this specification. A suitable austenitising temperature, not exceeding 955°C, is to be selected.

The tempering treatment is to be carried out within a temperature range of 600°C to 675°C. Water quenching from the tempering temperature is mandatory. When necessary, double tempering is permitted. Those restrictions specified for single tempering also apply to double tempering.
Large and complex forgings may be rough (semi-finished) machined prior to heat treatment. Semi-finished machining reduces the effective cross section and prevents quench cracking. All heat treatment operations are to be carried out using properly constructed furnaces. Austenitizing temperature is not to exceed 950°C. The tempering treatment is to be carried out within a temperature range of 600°C to 675°C. Water quenching from the tempering temperature is mandatory. Double tempering is permitted. Any restrictions specified for single tempering also apply to double tempering. When additional stress relief after primary heat treatment is specified by the purchaser or project authority, it is to be carried out at least 30°C below the final tempering temperature, but not less than 570°C. Water quenching from stress relief temperature is mandatory.

Lloyds LR Type 550 Mechanical Properties

Temperature

≤ 0°C 0 - 30°C

PROPERTY / VALUE

Tensile Strength

val1

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Elongation, A

≥ 16 %

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Reduction of Area

val1 %

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Yield Strength, Rp0.2

550 — 690 MPa

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Lloyds LR Type 550 International Equivalent Materials

Showing 1 of 2 results.

MATERIAL

STANDARD

COUNTRY / PRODUCER

EQUIVALENCE CATEGORY

MATERIAL

Q1 (Navy)

STANDARD

DEFSTAN

COUNTRY / PRODUCER

United Kingdom

EQUIVALENCE CATEGORY

Composition 100%

Equivalence categories reflect chemical-composition and mechanical-property comparison — always verify suitability against the governing specification for your application.

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2Cross References

40Composition
14Mechanical Properties
3Physical Properties
2Heat Treatment
-Metallography
-Machinability

-Stress-Strain
-Formability
-Fatigue
-Fracture
-Creep

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-Coatings
-Dimensions
-Tribology

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