Especificacion Acero 1821

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CORPORATE PRODUCT & PROCESS SPECIFICATION 1.0 SCOPE This specification covers surface appearance requirements for as-received unpainted hot rolled sheet, strip, hot strip mill plate, discrete plate, and quenched and tempered plate with a nominal thickness > 2 millimeters. 2.0 APPLICATION 2.1 1E1821, Change 00, was formerly a multiple variation specification. Engineering blueprints thatcontinue to call out a letter designation with 1E1821 are now satisfied by a commensurate letter designation with 1E4334 (please note that the letter designations are inverse). Former Blueprint Designation 1E1821B (Highest Quality) 1E1821A Figure 1 2.2 This specification is not intended to be applied to part-number engineering drawings where exceptional surface quality and appearance is essential onthe finished machine. This specification only covers plate cosmetic quality in a scale-free (e.g., shot blasted or pickled and oiled) condition. For plates and parts requiring very high levels of surface quality, refer to 1E4334 for requirements. This specification only covers as-received plate quality, and the quality requirements described herein do not apply to finish painted surfaces (refer to1E2001 for painted surface finish requirements). 3.0 DEFINITIONS 3.1 “Linear surface marks” are scratches defined as cold handling abrasions, hot sliding marks, hot roll gouge marks, reconditioning marks, or other markings on the surface with a length-width ratio of greater than 8. 3.1.1 “Scratches” or “Gouges” - Appearance varies from small, sharp indentation to large gouges with partiallyprojecting edges. They are distinguished from seams, laps, or cracks by a more rounded bottom, with less scale. There are two general classes as defined below. 3.1.2 Hot bed scratches tend to be perpendicular to the rolling direction and are a result of damage at the rolling mill. Excessive movement of hot plates on the cooling bed can also cause these types of defects. Since these occur while theproduct is still hot, they tend to be scaled and otherwise dull in appearance. The likelihood of these types of scratches occurring increases with increasing plate thickness and weight. See Figure 2 for examples of hot bed scratches.
THE INFORMATION HEREON IS THE PROPERTY OF CATERPILLAR INC. AND/OR ITS SUBSIDIARIES. WITHOUT WRITTEN PERMISSION, ANY COPYING, TRANSMITTAL TO OTHERS, AND ANY USE EXCEPT THATFOR WHICH IT IS LOANED, IS PROHIBITED. DATE CHG NO NUMBER

Governing Specification 1E4334A (Highest Quality) 1E4334B

SURFACE QUALITY - PLATE AND SHEET
Caterpillar: Confidential Yellow

06 SEP 2011

02

1E1821
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CORPORATE PRODUCT & PROCESS SPECIFICATION

Figure 2 - Hot Bed Scratch Examples 3.1.3 Coldscratches are typically bright and shiny, and can happen either at the steel mill or at Caterpillar. 3.2 Rolled-In Primary Scale - Furnace scale that is not removed by descaling and is subsequently rolled into the surface of the plate. A ‘pitted’ surface will remain after shot blasting. There are a variety of potential causes, including problems with the reheating atmosphere, poor descaling practices,excessive heating times, etc. An example of rolled-in primary scale is shown as Figure 3.

THE INFORMATION HEREON IS THE PROPERTY OF CATERPILLAR INC. AND/OR ITS SUBSIDIARIES. WITHOUT WRITTEN PERMISSION, ANY COPYING, TRANSMITTAL TO OTHERS, AND ANY USE EXCEPT THAT FOR WHICH IT IS LOANED, IS PROHIBITED. DATE CHG NO NUMBER

SURFACE QUALITY - PLATE AND SHEET
Caterpillar: Confidential Yellow

06SEP 2011

02

1E1821
PAGE 2 OF 15

- Reproduction Constitutes an Uncontrolled Document -

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CORPORATE PRODUCT & PROCESS SPECIFICATION

Figure 3 - Rolled-In Primary Scale 3.3 “Rolled-In Secondary Scale” - A “lacy” pattern on the surface of the plate with a shallow depth. Secondary scale is formed during hot rolling and not during reheating. Insufficient use of descaling sprays...