Web     This Site

 | Home | My Account | Post Article | Upload Showcase | Download | Site Shortcuts | Feedback | Partner | About us | My Tokens |

  Home > Consulting > Level 2 Model

Roll Design
Auto Form
Free Form
Mill Load
Flow stress
Hi-T Data
General Data
Mill Diagnosis


Classified Listing
Product Profile
R&D/Tech Profile


- Metallurgy & Materials
- Metal Working
- IT & Automation
- Industry Review
- Metal Patents
- Research
- Metal Directory
- R&D Roadmaps
- Steel Mills

Level 2 Model as a Metallurgical System


Controlled rolling with hold

A Level 2 model usually contains a module for the controlled rolling, in which metallurgical principles are applied to establish the controlled rolling schedules. The controlled rolling schedules are designed either by temperature or by the steel thickness.

In order to control the rolling material microstructure that is mainly influenced by the deformation temperature, the controlled rolling process can largely be divided into the three stages. At first the steel is rolled to a certain temperature such as 1000C (1850F) from a reheating temperature (e.g. 1120C, or 2050F). Then it is held on the table and is cooled by either water (e.g. as the thickness over 60mm) or air, until its temperature drops to about 850C (1550F). After the hold, the slab is completed rolling to final gauge by a finish temperature such as 850C (1550F). The temperatures for the controlled rolling should be different from grade to grade, and the values could be studied and stored in the expert system for the Level 2 to use.

Besides the deformation temperature, enough deformation amount should be pledged. Generally, the deformation should be more than 30% of the total thickness reduction. Some plants use the hold thickness as the four times of the finish gauge. In order to further improve the comprehensive performance and properties of the finish steel, Level 2 should assign a heavy draft in the finish stage. For simplicity, this heavy draft could be applied as the slab reaches the one-half of the initial thickness. In principle, this heavy draft should be applied in the pass(es) in which there is no significant grain growth exists and the heavy draft wont cause shape problem. Usually, the preferred value for the hold thickness and/or hold temperature, as well as the preferred pass in which the high draft applies, could be stored in the expert system for a given plant with a designated product range, to make it available for the Level 2 system.

In the hold period, there are microstructure evolutions. As a result, the flow stress changes. Many Level 2 models have no reflection of this change in the flow stress model.

Figure 2 Flow Stress Error vs. Resume temperature

Studies based on the history data of a Level 2 system showed that there were significant force errors in the resume passes (Figure 2). The force error was usually over 20%. The primary reason was due to the microstructural change during hold (recovery, recrystallization, precipitation, etc.) which was not taken into account in the flow stress formula of the Level 2 system.

<To be continued>

Part 1   |   Part 2   |   Part 3   |   Part 4


    Recent Update
Metal Pass recent papers
- Metal Pass mill-related projects
- Mill Level 2 project series
 Metal Pass tech supplies
Consulting - Ask a question
- More ...
    Roll Pass

 Design: AutoForm

 Mill Load

 Design: FreeForm

    Flow Stress Models
Fe-alloy Hot F2 F2F3 A B C
Cold F2 F2F3a - - -
Non-Fe Hot F2 - A B C
Cold F2 F2F3a - - -
   Mill Projects     Ranks
   Publication     Biz Tools
   Submission     Domains
    Project Series
Mill model improvem. projects
Mill related modeling projects
Metal Pass recent publications

| Private Policy | Terms & Conditions | About Us | AdvertisePartnerInvestorSponsorlistings |  

Copyright: 2009 Metal Pass LLC. All rights reserved