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Technical nomenclature of the sheets

Aceros URSSA > Technical information > Technical nomenclature of the sheets

WEAR RESISTANT FACTOR

In order to facilitate the appropriate selection of the quality anti rust and abrasion sheets, we develop this wear resistant formula.

To do this was taken as a basis the wear resistant that offer a conventional steel layer (ST 37), with hardness Hb and factor 20 (100 Hb / 5 = 20) and the full alloy sheet or special thermal offered with hardness of 500 HB that corresponds to 100 factor.

In the catalogue are included from the 35 (S355JR) factor to 100 factor of the tempered and annealing sheet (URSSA-500).

DESIGNATION OF STEEL ACCORDING TO:

The UNE EN 10027-1 rule establish the rules for the symbolical designation of the sheets by numeric symbols and letters that express certain mechanical, physical, application characteristics, necessaries to set an abbreviate designation of the sheets.

Designation of structural steels departing from its characteristics.

1st letter

Type of steel

nº Elastic limit

2nd Resilience letter

3rd
Test letter

Following letters

Following letters

Other characteristics

E

Engineering

Steel for mechanical constructions

Indicate the minimum elastic limit warranted in N/mm2

J

Res. de 27 Jul.

R

Res. 20º

C

Special cold reduction

A

Soft –
Annealed

Soft –
Annealed

L

Pipe – Line

Steel for pipelines

K

Res. de 40 Jul.

0

Res. 0º

M

Thermomechanically rolled

AR

As Rolled

As Rolled

P

Presure

Steel for boilers

L

Res. de 60 Jul.

2

Res. -20º

N

Normalized or controlled lamination

N

Normalized

Normalized

S

Structural

Structural steels

3

Res. -30º

Q

Quenched and Tempered

N+T

Normalized and Tempered

Normalized and Tempered

4

Res. -40º

L

Quenched and Tempered

Q

Quenched

Quenched

5

Res. -50º

H

Resistance to high temperatures

Q+T

Quenched and Tempered

Quenched and Tempered

6

Res. -60º

W

Resistant to atmospherical corrosion

T

Tempered

Tempered

S

Shipbuilding

TM

TermomechanicallyRolled

Termomechanically Rolled

G

Other characteristics

TM+A

TermomechanicallyRolled +accelerated-cooling

Termomechanically Rolled +accelerated-cooling

The UNE EN 10027-2 rule establish the rules for the numerical designation of the steels. The same number may correspond to one type and degree steel, and for each degree and each type corresponds a unique number as the following example:

1. NN XX (XX)
1 indicate that is steel
NN is the number of the group of steel, according to each use.
XX (XX) is the order number (in parenthesis, future extension)

Carbon equivalent

One of the most important characteristic in the steel is the solderability, that can be evaluated through the carbon equivalent parameter.

Formulas for calculating the equivalent carbon:

Short formula:

Ce = C +  Mn
6

Long formula:

Ce = C +  Mn  +  Cr + Mo + V  +  Cu + Ni
6 5 15

Soldering/welding

To determine if a steel should be preheat:

A) If Ce > 0,38, The steel need a preheating.

B) If Ce ≤ 0,38, does not need a preheating.

In the case that the material should be preheated and is not do it, the welding will cool down so fast (coat if the room temperature is very low) and the mass will not have enough time to turn to ledeburite and perlite ( or cementite and perlite when it refers to a hipereutectoide steel. This would result to microcranks.

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