ARE SMALL ROLLS TO BE CONSIDERED AS COMMODITIES? Dr. Karl H. Schröder. Technical Director British Rollmakers (China) Ltd

Transcription

1 ARE SMALL ROLLS TO BE CONSIDERED AS COMMODITIES? Dr. Karl H. Schröder Technical Director British Rollmakers (China) Ltd Primer Congreso y Exposición Nacional de la Industria del Acero Monterrey, N.L., Mexico Presentation Overview Small Rolls and Commodities Some remarks on the Roll Foundry Industries How to make Small Rolls as non-commodities Analogies between Cutting Tools and Rolling Mill Rolls Conclusions on further expectations with Small Rolls. 1

2 Rolls are Tools for Rolling Mills of limited service life. COMMODITY Goods that can be bought or sold anywhere without any special or unique specifications Example: Pig Iron, Oil, Gasoline, Screws The manufacturer of these goods is of lesser significance For sure, commodities can be very critical parts in many applications 2

3 ROLLS Strictly specific concerning the geometry and the dimensions. The Rollmaker is of minor importance - despite all the wonderful specifications such as hardness, roll grade, composition, and mechanical properties. Most Rollmakers are capable of meeting all requirements. The Performance of Rolls from various suppliers is often within a narrow span There are many standard Roll Grades in the market, variations of : Nodular Iron Adamite ICDP HChr It is the duty of the smart Sales People and Technical Services people to find the best suitable grade. But the Mill people are always helpful. Only if the Roll Grade is a commodity then they can really bargain! 3

4 Are small rolls to be considered as commodities? YES! This might be boring, but!!! competition is hard and tough!!! There have been and there will be Non-Commodities Roll Grades in the market but never for long Non-Commodity Rolls become Commodities FAST! Right now. Carbide Enhanced HChr is on the way to become a Commodity. Carbide Enhanced ICDP are protected by Patents Imitators fake and turn these Grades into Commodities illegally! HSS -? And in the Future, we expect more results from R&D 4

5 Who are manufacturing Small Rolls, and why? 1 - Selling Price 2 - Material cost 3 - Total Manufacturing Costs Fig. 1: Roll manufacturing costs and selling prices as function of roll weight 5

6 Fig. 2: Different roll manufacturing costs in percentage of total roll manufacturing cost as a function of roll weight Labor Costs Calculation Salary Total Labor Costs = Productivity wherein: Total Labor Costs is Money per unit Roll Weight (Kg) and includes all payments to person in manufacturing, sales & service, overhead Salary is Money per Hour Productivity is (Kg / h) is a function of the weight of rolls, because machining and treatment times (main working time) decreases with decreasing roll weight much faster than side times (handling, mounting, de-mounting from machines, centering, testing, etc.) Automation is limited ( CNC, robotics ) due to low numbers of identical rolls. 6

7 Small Rolls to be considered as Commodities means: costs-cutting on manufacturing, services, and support no more R & D, not affordable anymore high-tech Rollmakers may have to give up Small Rolls very little or no progress at all business goes to the cheap producers Wherein: Roll Cost Roll Efficiency = Performance Roll Cost means Money per Unit Roll Weight Performance means Kg of Roll per unit weight of finished product (e.g. 1000t) In case the Performance of All Rolls is Equal => Commodity! In case the Performance of a particular Grade is High => Non Commodity! - Sales Price might be High! For Example: Last stands of wire rod mills; Acicular Nodular Iron versus Hard Metal (WC) ; Price and Performance of Hard Metal is High, Roll efficiency for Hard Metal is better than that of Nodular Iron (Commodity!). 7

8 But there is big potential for practical development: Better Wear Resistance and: longer rolling campaigns less downtime of the mill for roll change less redressing time for the rolls better tolerances of the products better surface of the products Fig. 3: Wear resistance of grey cast iron versus carbide content and hardness 8

9 Fig. 4: Typical roll grades, their hardness range and content of carbides (Range of alloys: % C, % Si, % Mn, % Cr, % Mo, % V and % W) [13] Fig. 5: Wear versus alloy equivalent 9

10 Roll improvement does NOT mean: gambling with Hardness small variations of alloying elements variations in Heat Treatment Though these might be necessary and useful to increase Roll Safety Roll improvement means: more high hard special Carbides (Enhancements) new materials : HSS, WC, Ceramics Fig. 6: Information about carbide forming elements, types of carbides and some hard particles. 10

11 The development of Rolls follows the development of Cutting Tools. Cutting Tool Materials Roll Materials Fig. 7: Roll Grades & Materials for cutting tools 11

12 Range represents variations due to variations in microstructure & hardness Alloy Equivalent (AE) Fig. 8: Wear diagram as guideline for development of new roll grades To rate Rolls we have to look beyond Pricing alone: specific and total Roll performance safety against Rolling accidents support and services from Roll vendors total average cost per unit weight of Rolled Product. 12

13 Are Small Rolls to be considered as Commodities? Not necessarily! Small Rolls offer high potential for new materials/grades. The super high tech has already reached the last stand of some mills with hard-metal and ceramic-rolls. Roll development seems to be very slow most of the time (commodities?). Occasionally, there are big improvements in short times (High-Chrome-Iron; High-Chrome-Steel; HSS, Carbide Enhancement) Rolls will always remain as Tools.. but with the service life increasing.., maybe someday they may even match the lifespan of the mills and they will become capital assets! But for certain, they will always require that special maintenance. BRC sells commodities, of course, and is very competitive! but the idea for the future is to add R&D to good roll commodities to achieve the Best Roll Concept 13

14 Move Up With Us 1. Tool Steel 2. High Speed Tool Steel HSS 3. Coated HSS 4. Hard Metal HM 5. Coated HM 6. CBN - Cubic Boron Nitride 7. PKD - Polycrystalline Diamond 8. Ceramics Fig. 9a: History of cutting tool grades 14

15 A - Mild Hard B - Nodular Iron C - Indefinite, IC C - Carbide Enhanced IC D - High Chrome HChr D - Carbide Enhanced High Chrome Fig. 9b: History of roll grades 1 - Tool Steel Adamite 2 - High Speed Tool Steel HSS 4 - Hard Metal HM 8 - Ceramics 15