Yassı çelik haddelemede kullanılan sıcak şerit haddehane hadde merdanelerinin aşınma parametrelerinin optimizasyonu ile servis ömürlerinin uzatılması
Optimizing the parameters of wearing of hot strip mill work rolls and increasing roll service life that used in the flat steel manufacturing
Yazar: CANER TOPTAŞ
Danışman: PROF. DR. CEVAT ERDEM İMRAK
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / Makine Mühendisliği Ana Bilim Dalı / Konstrüksiyon Bilim Dalı
Derece: Yüksek Lisans, 2015
Konu: Makine Mühendisliği = Mechanical Engineering
Dizin: Aşınma dayanımı = Wear resistance ; Eddy akımları = Eddy currents ; Haddeleme = Rolling ; Mekanik dayanım = Mechanical strength ; Merdane = Roller ; Optimizasyon = Optimization ; Taşlama = Grinding ; Ultrasonik test = Ultrasonic test ; Yüzey aşınması = Surface wear ; Yüzey çatlağı = Surface crack

Özet:
Demir çelik sektöründe yassı mamul üretiminin gerçekleştiği haddehanelerde kullanılan ve nihai mamul kalitesini belirleyen hadde merdanelerinin tüketimleri, işletme maliyetlerini etkileyen en önemli yedek malzeme girdisidir. Hadde merdanelerinin üretimi farklı imalat süreçlerinden oluşmakla beraber, henüz Türkiye' de imalatını gerçekleştirebilen bir firma bulunmamaktadır. Özellikle Avrupa, Amerika ve Japon firmaları, geçmişten günümüze merdane üretiminde öncü olan ve gelişmiş üretim teknolojileri içeren tesislere sahiptirler. Türkiye' de yassı mamül üreten demir çelik fabrikaları, bu bakımdan yabancı firmalara bağımlıdır. Bu tip malzeme girdilerinin dış ülkelerden temin edilmesi nedeniyle hem sanayi tesisleri hem de ülke ekonomisi olumsuz yönde etkilenmektedir. 
Bu amaçla bu çalışmada, yassı demir çelik mamül üretiminde kullanılan ve haddeleme işleminin yapılmasını sağlayan iş takımlarından biri olan sıcak şerit haddehane iş merdanelerinin çalışma yüzeyi aşınma parametrelerinin optimize edilmesi ile merdane kullanım ömrü ve çalışma sürelerinin uzatılması amaçlanmıştır. Merdane çalışmasına etki eden parametrelerin servis sürelerine olumlu ve olumsuz yönde etkileri belirlenerek bu parametreler açıklanmıştır. Parametrelerin birbirine olan etkileri tespit edilmiş, en iyi çalışma parametrelerinin bulunması sonucu bu bulgular belirlenerek, merdanelerden tüm kullanım ömrü boyunca alınan toplam verimin arttırılması ve tüketimlerinin azaltılmasının sağlanması amaçlanmıştır.
Çalışmada kullanılmak üzere aşınmaya karşı diğer merdane kalitelerine göre daha iyi performans gösteren yüksek hız çeliği kalite iş merdaneleri seçilmiştir. Merdane maksimum servis ömrü, merdanenin servisi esnasında çalışma yüzeyinde oluşan ve aşınma sonucu görülen nihai mamül kalitesine olan kusurların haddelenen mamule etkisi ile belirlenmiştir. 
Bu amaçla merdanelerde oluşan aşınma etkisinin doğru tespit edilebilmesi amacıyla nitel ölçüm sistem analiz çalışması yapılmış, böylece süreç değişkenliklerinin etkisinin azaltılması sağlanmıştır. Yapılan çalışmalarda  farklı kullanım pratikleri denenmiştir. Çalışma sonucunda en iyi kullanım şartları elde edilmiş, merdane yüzey aşınması kontrol altına alınarak daha uzun servis ömürlerinde çalışabilmeleri sağlanmıştır. Yapılan pilot çalışmalar sonrası doğrulama çalışmaları da yapılarak proje sonlandırılmıştır. Çalışmanın maddi getirisinin yanında, iş sağlığı ve güvenliği açısından katkı elde edilmiştir. 
Yabancı ülkelerden yüksek bedeller karşılığında ithal edilen merdanelerin tüketimlerinin azaltılması sayesinde merdane kullanım ömürlerinde artış elde edilebileceği gibi maliyetlerin düşürülmesi yönünde de önemli bir katkı sağlanılmasına yardımcı olunacaktır.

Abstract:
The rolling mill process is one of the methods frequently that are used in plastic forming processes. The rolling is usually the name given to the process using a mold to shape the steel based material. The flat steel rolling is made with cylindrical shape rolls and slab steel is passed through rolls. The rolling in sheet metal and steel mills is one of the main processes on flat steel production.
The flat steel production is divided into hot and cold rolled process depending on temperature. The rolls that are used in the rolling mill process should be in accordance material quality and they are important tools that provide continuity of production.  Because the mill rolls of the desired performance properties produce thereby during the extrusion process and ensure that the quality of the rolling mill are direct effect on productivity. Defects must be solved by manufacturing or grinding process. If there is a defect on the roll, the roll can spall during rolling process depending on variable rolling load and temperature. 
The rolls are faced with extreme operating conditions and their working surface can not maintain the properties normal working surface. The result of the deterioration of the roll surface conditions, the rolls are replaced with the new grinding rolls. The services out rolls are grinded on grinding machine in order to ensure to serve.
Rolling mills rolls which determine the final product quality are the most important equipment in the mill. Rolls complete their working life under harsh conditions without damage is not always possible. The rolls occur either scrapped or replaced with new grinded rolls during their service life. These changes lead to disruption of production or to stop the rolling mill process. As a result of this attitude in the year experienced a significant amount of production losses. However, the mill is able to work without the need to change will further increase anuual production tonnage. But not yet developed such a roll quality. Again continuous roll quality has also improved from past to present and available to the durable quality rolls different sectors of the difficult working condisitons. This is one of quality high speed steel quality rolls with superior wear performance disconntected from one side to the other quality roll performance of these rolls can not be taken without proper working condisitions are provided for each rolling mill.
The consumption of mill rolls that are used in the mills where the flat products are produced and that determine the quality of end products are one of the most significant input of relay which effects the operating cost in iron and steel industry. Although the productions of rolling mills have different manufacturing process, there is no company in Turkey that can perform its manufacturing. It can be said that the companies that are based in Europe, the USA, Japan have advanced manufacturing technologies in the production of rolls from past to present. Because of that reason, the steel companies that produce flat products are dependent on foreign companies. It can be said that since these kinds of products are imported from abroad, the economy of the country and the industrial sector has been adversely affected in that respect.
To this end, manufacturers of rolling mill rolls to make more long-lasting performance and continuous research on new high quality rolls that affect the manufacturing process. Especially Japanese roll manufacturers are pioneers about this issue and they developed abrasion resistant quality rolls as know high speed steel rolls according to other roll qualities. But there is not a guarantee that it will work with every quality rolling mill rolls with high performance in all operating conditions. Because of that the rolling mill people must search to find the right working conditions together with right roll quality. These studies include the plurality of parameters.
For this purpose, the aim of this study is to look at the parameters of wearing of hot strip mills that are used in the factory which produces flat steel products, then to optimize them and to extend the duration of usage of these mills in working life. Thanks to the working  parameters obtained , the positive and the negative effects of parameters of the services have been determined. Also, the mutual effects of these parameters have been found and as a result the best option has been selected to maximize the overall efficiency of mills during its life span and to minimize its consumption during its operation.
For the case study, high speed steel work rolls that exhibit superior performance against wear and used in hot mills that have been chosen. The sheet material defect is seen the result of roll wearing at the service and it was choosen as the output data of maximum roll life. 
To this end, the qualitative measurement system analysis has been conducted, and as a result it is aimed to reduce the impacts of the variability of the process. Also by the help of the studies, different work practices have been implemented and tested. The results of studies  revealed the best working conditions of the rolls and by controlling the roll surface wear, the longer service life of mills have been guaranteed. The projects have been terminated after the validity check and pilot productions. Besides the financial benefits gained overall, the project also contributed to occupational health and safety when it comes to operate the rolls.
In this study was made the determination of the parameters affecting the roll surface wear, selecting the appropriate value according to the parameters of the working conditions, according to the test results to obtain a final product quality, the revision of the working conditions based on the best results obtained according to the test results, improving the work life issues due to roll wear after revisions were examined. 
If provided with other benefits is to spent grinding rolling mill rolls of labor, spare parts and energy saving. During the year the amount of grinding required to make to move made grinding roll grinding has been reduced nearly to profit from labor and power looms.
The study consists of six chapters. In the introductory chapter was discussed the importance of invervening of the rolls that used in the factory of iron and steel. The basic features mentioned in the production of flat steel products, hot rolling and cold rolling processes by introducing mechanical issues have been considered in the second chapter. The basic information of hot strip mill operations in the iron and steel production and function of the overall system main equipment jobs are described and given in the third chapter. General hot strip mill rolls, their type and quality specifications properties, manufacturing process have been mentioned in the fourth chapters. Theoretical concepts related to the erosion of the roll working surface are discussed in the fifth chapter and information about the factors affecting the life time are given. The main parameters are discussed about the working surface wear of high speed steel work rolls and the wearing parameters have been made efforts to extend the life time of rolls in order to ascertain the different effects with each other. The importance of this study and future stage information are discussed in the sixth chapters.
Especially the completion of the normal working life of the rolls kept at normal levels all work rolling and the work surface during the service life of the rolling rolls which determined leads to a prolongation of the working life. A significant gain of rolling mills in Turkey when the country's economy must be kept in mind will not be considered unless made available.  
In the future stages of study can be done further work to reduce the roll consumption. One is to optimize the amount of grinding. The amount of roll grinding and similar work on the project surface eddy current crack controls, the hardness control to make in each grinding step and can be controlled by ultrasonic examination. Case studies will be provided on the implementation of similar projects with F5-7 work rolls to be run without the need to change rolls of all stripes rolls. But firstly it is developed to be resistant to abrasion quality similar to high speed steel quality platen rolls used in the rolling mill machine are required. The working conditions of high speed steel of the counter in the last three rolling mill machine are not appropriate for the moment to run them here.
Another issue is the rolling mill rolls can not be produced in Turkey. The roll manufacturing is a manufacturing that involves serious information that reguires special manufacturing technologies and engineering know-how. However with the increasing production of iron and steel rolling mills in Turkey is also a need to be generated. High costs, long lead times from foreign countries and use the money instead of rolling mill rolls for rolling mills imported domestic manufacturing economy will be one of the most significant gains.