This manufacturing method for a slab is a method for manufacturing a slab by a continuous casting equipment including a twin-drum type continuous casting apparatus, a cooling apparatus, an in-line mill, and a coiling apparatus. The method includes calculating a friction coefficient from measured values of a rolling load and a forward slip when the slab is rolled, by use of a rolling analysis model, and controlling a lubrication condition during rolling of the slab so that the friction coefficient falls within a predetermined range, wherein, when the friction coefficient is calculated from the measured values of the rolling load and the forward slip by use of an Orowan theory and a deformation resistance model formula based on a Shida's approximate formula as the rolling analysis model, the predetermined range is 0.15 or more and 0.25 or less.

This manufacturing method for a slab is a method for manufacturing a slab by a continuous casting equipment including a twin-drum type continuous casting apparatus, a cooling apparatus, an in-line mill, and a coiling apparatus. The method includes calculating a friction coefficient from measured values of a rolling load and a forward slip when the slab is rolled, by use of a rolling analysis model, and controlling a lubrication condition during rolling of the slab so that the friction coefficient falls within a predetermined range, wherein, when the friction coefficient is calculated from the measured values of the rolling load and the forward slip by use of an Orowan theory and a deformation resistance model formula based on a Shida's approximate formula as the rolling analysis model, the predetermined range is 0.15 or more and 0.25 or less.

The present invention provides a modeling and manufacturing method for a reversible plow point with the characteristics of a low resistance and being strong inside and hard outside. By means of performing parameter optimization, three-dimensional modeling and numerical simulation analysis on a curved surface of a plough point, parameters, i.e. a plowshare angle .sub.0, a plowshare surface angle , an included angle between a soil trace and a plowshare edge, and a soil lifting angle , at which the lowest working resistance is achieved, are determined, and composition optimization design and die forging-machining-carburization-quenching-tempering treatment are performed on a base material of the plough point, such that a new reversible plow point with the characteristics of a low operation resistance, high strength toughness of a core portion, and high wear resistance of a surface layer is obtained. The present invention can effectively solve the problems of wear, failure and resistance increase which easily occur due to a plough point being subjected to high-speed impact and wear from soil, sand, stones and root blocks for a long period of time during a service process, and the present invention is expected to be widely applied to the field of manufacturing of soil contact components of agricultural machinery.

A method for collecting mill scale from a hot rolling mill is provided. The hot rolling mill includes a flume. The method includes transporting mill scale particles in wastewater, retrieving the wastewater from a flume of the hot rolling mill and separating the mill scale particles from the wastewater using a separator. A hot rolling mill and a method for retrofitting a hot rolling mill are also provided.