"METALTEHNOMASH" Metallurgical technology for mechanical engineering

Development of efficient low-cost solutions to improve the work rolls cooling system of finishing stands of WS HSM 2000.

Period: 2004-2005
Customer: OJSC "NLMK"

The aim of the work is to analyze the current state of the work rolls cooling system and preparation of proposals to improve its efficiency at minimum cost in the shortest possible time.

Additional information

THE MAIN SECTIONS OF WORK:

1. A SURVEY OF THE EXISTING COOLING SYSTEM OF ROLLS

2. ANALYSIS OF THE OPERATING TEMPERATURE OF ROLLS

3. ASSESSING THE IMPACT OF TEMPERATURE ON THE ROLLS OPERATION AND FORMING THE CROSS-SECTIONAL PROFILE OF THE STRIPS

4. MODELING OF THE ROLLS COOLING CONDITIONS

5. DEVELOPMENT OF RECOMMENDATIONS FOR IMPROVING THE COOLING SYSTEM OF WORK ROLLS

APPENDIX 1. JUSTIFICATION OF THE PARAMETERS CHOICE, DIAGRAM OF LAYOUT AND CHARACTERISTICS OF WORK ROLLS COOLING SYSTEM IN FINISHING STANDS.
APPENDIX 2. CERTIFICATE OF INSPECTION OF THE EXISTING OF ROLLS COOLING SYSTEM IN FINISHING STANDS OF WS HRM 2000 2000.

Compliance of jets traces with their position
and orientation on the cooling collectors
Circled in oval is nozzle and its trace, the straight lines are the places of sections joining and the corresponding breaks of cooling zones in a three-sections collector

Surface plan of the existing cooling system with two-line collector in one of the stands, as well as water flow rate over the roll barrel length.

The proposed configuration of the cooling system of the upper roll in one of the stands of the finishing group of WS HRM 2000.

Surface plan of the roll with cooling zones from the entrance and exit sides, as well as the total coolant consumption running along the length of the roll barrel in accordance with one of the proposed cooling configurations.

The main results
1. It was determined the values of uneven cooling and temperature gradients along the length of rolls barrel, the parameters of the cooling system efficiency, places of inaccurate collectors manufacturing and nozzles seats orientation in the collectors.
2. Stability studies of rolls temperature, their wear and the cross-sectional profile of the rolled strips revealed the reasons for the formation of local thickenings and thinning on the transverse profile of hot-rolled strips.
3. On the basis of measurements and by using the method of experimental determination of the rolls cooling topography (Spray Impact Method) it was determined the real scheme of work rolls cooling in all finishing stands, which, combined with measurements of rolls temperature (as well as other parameters of the rolling and cooling) allowed to adapt the mathematical model of the thermal state of rolls and to determine the possibilities of the existing cooling system improving.
4. The necessary types, the total number of nozzles and the parameters of their orientation are adjusted, collector design is developed that will improve the efficiency and uniformity of rolls cooling. It is achieved the work rolls temperature reduction in the most heat-loaded stands by 5-6C, which provided a reduction of rolls wear, thus, improving the surface condition of hot-rolled strips and reduce local thickening of the transverse profile.

Survey of the coolant supply system on the mill rolls of 4-stands 1400 SRS-5 and development of recommendations for improving its effectiveness

Period: 2005
Customer: OJSC "NLMK"

The aim of the work is to conduct a survey, fulfill analysis of the current coolant supply system, as well as the preparation of proposals for improving its efficiency.

Additional information

THE MAIN SECTIONS OF WORK:

1. A SURVEY OF THE EXISTING COOLANT SUPPLY SYSTEM
1.1 General characteristics of the system
1.2 Specification of nozzles
1.3 Actual coolant supply schemes, condition of cooling reservoir, the orientation of nozzles
1.4 Experimental investigation of impact (work) zones of nozzles at the work rolls and backup rolls
1.5 Analysis of test results, the main conclusions

2. EXPERIMENTAL STUDY OF OPERATION TEMPERATURE OF ROLLS
2.1 Rolling modes and the associated changes in patterns of bulk temperature of work rolls
2.2 Measurement of the temperature distribution along the length of the work rolls barrel
2.3 Thermal imaging and temperature measurement of rolls and strip

3. DEVELOPMENT OF RECOMMENDATIONS FOR IMPROVEMENT OF COOLANT SUPPLY SYSTEM
3.1 Modeling coolant supply on the rolls in the existing system
3.2 The selection of rational parameters of the coolant supply system
3.3 Expected efficiency of coolant supply system modernization

APPENDIX 1. CERTIFICATE OF INSPECTION OF THE EXISTING ROLLS COOLING SYSTEM

Misoriented nozzles of work roll cooling
reservoir and bad nozzle in the center

Compliance of jets traces with their position and orientation
in the cooling collectors (results of the experiment).

The current scheme of coolant supply and distribution along the length of the work roll in one of the stands

Example of non-uniform coolant supply influence on temperature field in the work roll

The main results
1. Determined local and general problems of the existing system of coolant supply on the rolls.
2. Investigations are carried out of the rolls operation temperature, it is shown significant unevenness of temperature fields along the length of rolls barrel, which reduces the flatness of the surface condition of strips, as well as increases the thermal stresses in rolls and their spalling.
3. Proposals are prepared to improve the efficiency of the coolant supply system. In particular, the parameters are calculated of coolant supply on the work and backup rolls depending on their purpose and placement (types of nozzles, their flow rate characteristics, angles of sprays, angles of nozzles inclination фтв installation into collectors, step of nozzles).