Knowledge of Chinese Bar Roll Turners

1. The production line of a small continuous rolling mill, its rolling unit consists of ∮550×4+∮450×3/∮380×4/∮380×2+∮320×4—17 rolling mills.

2. Small continuous rolling mills produce ∮12-∮40 round steel and ribbed steel bars, which are delivered in straight bars with a length of 6-12m.

3. The steel types rolled by the small continuous rolling mill are: carbon structural steel, high-quality carbon structural steel, low-alloy steel, and alloy structural steel.

4. The billet size used in the small continuous rolling mill is 150×150×9500mm and 120×120×9500mm, and the non-fixed length billet is 6600-9500mm.

5. The phenomenon of increasing the roll gap during rolling is called roll jump; the part of the roll where the bearing is installed is called the roll neck.

6. There are three types of looper formers. Small continuous rolling mills use two types of loopers: side loopers and vertical loopers.

7. The roll lathe is composed of the bed part, the thimble frame part at the end of the bed, the bed part, the tool rest part, the center frame part, and the chuck part.

8. When the roll is ground each time, not only the worn hole pattern should be repaired, but also the hot crack should be repaired as much as possible to improve the service life of the roll.

9. From the beginning of use to the scrapping of the roll, the percentage of the total weight of the roll to the nominal diameter of the roll is called the heavy-duty rate of the roll.

10. The factors affecting product quality and output from a technological point of view are pass design, roll pass turning, installation and adjustment of guide devices, roll installation and rolling adjustment.

11. The selection of the feed amount when processing the roll should be determined according to the depth of cut, the hardness of the roll and the product specification.

12. The automatic feed amount can only be used when the roll is blank, and it should be adjusted manually when the roll is finished to prevent the roll from appearing cycle ellipse.

13. The hole pattern work template is generally called the male template, and the proofing template is called the mother template. The male template is used when matching the hole pattern of the car, and the mother template is used for proofreading the male template and grinding turning tools.

14. The supporting tool placed under the cutting part of the turning tool is called the top of the knife. The shape of the upper end of the top of the knife should be made according to the shape of the blade.

15. When installing the roll turning tool, the turning tool must be fixed firmly to avoid the turning tool bending and the blade falling off after being subjected to cutting pressure.

16. The main technical requirements for turning tools used in turning rolls are high hardness, good wear resistance, and no reduction in hardness after heating.

17. Carbide knives YG6 and YS10 are suitable for turning cast iron rolls, and carbide YT5 is suitable for turning steel rolls.

18. The grinding process of the cutting edge of the forming model turning tool is composed of three steps: scribing, rough grinding and fine grinding.

19. Two types of grinding wheels commonly used for grinding turning tools are ordinary alumina diamond grinding wheels and silicon carbide diamond grinding wheels.

20. The material used for the rough rolls in the small continuous rolling mill is 170CrNiMo, which is a semi-steel roll.

21. The roll material currently used for the finishing rolls in the small continuous rolling mill is nickel molybdenum ductile iron, the surface hardness of the rolls is HS 60-80, and the depth of the hard layer is 40-50mm.

22. The maximum furnace temperature of the heating furnace cannot exceed 1200 °C. The temperature of the preheating section should be 900°C.

23. Hardness is an important quality index of the roll, which determines the wear resistance and service life of the roll. The repair and turning amount of the pass should be determined according to the actual wear degree of the pass.

24. The shape of the guide wheel is based on different parts of use and different product varieties. Generally, there are three kinds of oval holes, diamond holes and special-shaped holes.

25. Rolls can be divided into soft rolls according to their surface hardness, HS is 30-40; semi-hard rolls, HS is about 40-60; hard rolls, HS is about 60-85; extra-hard rolls, HS is about 85- 100.

26. Cast iron rolls can be roughly divided into chilled cast iron rolls, fine-grained alloy cast iron rolls, and ductile iron rolls.

27. The walking beam of the heating furnace in the small continuous rolling mill has four functions: loading, withdrawing, stepping, and overhauling.

28. The function of metal pressure working is to change the shape and size of the metal through plastic deformation.

29. The material of the roughing roll turning tool is high-speed tool steel, and the grade is W18Cr4V.

30. The advantages of the ellipse-round hole type system: the deformation in the hole type is relatively uniform, the cooling of each part is uniform, and the finished product can be produced in the middle pass.

Some common concepts

1. Roll gap – the distance between the two roll rings during rolling is called the roll gap.

2. Finished pass – refers to the last pass to roll out the finished product.

3. Full continuous rolling (endless rolling) – is to weld the continuous casting billet head to tail, so as to achieve uninterrupted rolling.

4. Continuous rolling – a rolling piece passes through several rolling mills at the same time, and the rolling in which the volume of the rolling piece passing through each rolling mill in unit time is equal is called continuous rolling.

5. Roll wear – the change in the surface quality and quantity of the roll caused by the contact of the roll with the rolling piece during the rolling process is called roll wear.

6. Rolling groove – the working part of a roll used to roll the rolling piece, that is, the roll surface of the contact part between the roll and the rolling piece during rolling is called the rolling groove.

7. Pass – the geometric figure formed on the rolling surface by the grooves of two or more rolls is called a pass.

8. Rolling force – the force of the rolling stock on the roll during the rolling process.

9. The working diameter of the roll – refers to the diameter of the contact between the roll and the rolling piece.

10. Elongation – the increase in the length of the rolling stock is called the extension.

11. Widespread – the width difference of the rolling stock before and after rolling is called the widespread.

12. Pass system – the billet is rolled through several passes until the product is rolled, and the set of passes used is called the pass system.

13. The heavy turning rate of the roll – the ratio of the total heavy turning weight of the roll to the nominal diameter of the roll is called the heavy turning ratio of the roll from the beginning of use to the scrapping.

14. The durability of the tool – the total cutting time of the tool from the start of cutting until the wear amount reaches the blunt standard is called the durability of the tool.

15. Tool life – From the time a new tool is put into cutting until it is scrapped, the total cutting time is called the life of the tool.

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