My Masters Work
NEW METAL ECONOMY METHOD OF ROLLING OF THICK LEAVES WITH LONGITUDINAL PROFILING
The production of rental on thick leaves mill is characterized the high specific expense of metal. Output suitable 0,78 - 0,85 makes on the operating thick leaves mills of Ukraine. The basic stake of wastes at rolling of thick leaves (to 90%) is made lateral and butt end edge. Therefore important by the economy of metal at rolling there is approaching of form of the prepared rolls of sheets in a plan to rectangular.
The most effective and technically simple method of diminishing of expense of metal at rolling of thick leaves is a management the form of rolls in a plan.
Such management allows to get the compensating form of lateral verges of rolls, which in the process of extraction at laying out of width will provide approaching of form of rolls in a plan to rectangular, instead of protuberant as in general case. For indemnification the unevenness of flow of metal on the angular areas of butt end and his central part as compensating it is expedient to get the concave form of butt ends.
During researches for creation of compensating form carried out the longitudinal profiling at which in a longitudinal passage-way a roll on the initial area of profiling was wrung out on a linear law to some value of the relative wringing out. Then rolling was continued with the set wringing out and after achieving the eventual area of profiling vice versa reduced wringing out to the zero by the end of standard. This profiling allows to get the required concave form of lateral verges at subsequent transversal passage-ways.
Researches of parameters of change form rolls in a plan executed in laboratory terms by the physical design of terms of rolling of sample from carbon steel in the horizontal felling of draft cage of thick leaves mill with the scale of design 1:20. Rolling was conducted on a laboratory figure 250 DonNTU, intended for the design of processes of the sheet rolling on the standards of plasticizes and leaden. Diameter of workings rollers of laboratory figure of 50μμ.
Designing material was choose plasticine, frappe to 6 - 8 oC. Conducted rolling of two series of standards-sample of plasticines the sizes of HcxBcxLc=15x90x(100 and 140) of mm with extractions at laying out of width λ=1.5 and 2.0 for every series.
Rolling was executed with laying out by widths in transversal passage-ways.
As a parameter of form of rolls in a plan adopted the relative bulge (concavity) of butt ends of roll after laying out of width . Independent variables, having basic influence on the parameter of change form, were adopt attitude of width toward length of sample ; stake of the profiled area at general length of sample 2Lnp/Lo, where Lnp is length of the profiled area; relative wringing out at profiling and coefficient of extraction at laying out of width .
It was set as a result of experiment, that the verges of butt ends of roll after laying out of width have a concave, even and protuberant form.
On graphecs influencing of change of variables of Lnp, ε, λ and Bo/Lo is shown on the parameter of form of butt ends of roll in a plan after laying out of width.
From picture 1 evidently, that at the defined variable of Lnp ε λ and Bo/Lo butt ends of roll after laying out of width can be even f=0. Consequently, for the set values Bo/Lo and λ it is possible to define optimum variable of ε and Lnp at which minimum curvature of butt ends of roll is provided after laying out of width.
The regressive processing of experimental data allowed to get the mathematical model of parameters of form of butt ends of roll after laying out of width. Adopted the model of the first order.
f/Bo=-0,0305+0,0144(Bo/Lo)-0,0411 (2Lnp/Lo) - 0,0035ε+0,0385λ, (1)
A middle error of approximation was 12%, coefficient of correlation - 0,942.
The analysis of the got results of mathematical design allowed to offer the new method of rolling of thick leaves with longitudinal profiling of rolls, which became the effective and technically simple method of receipt of thick leaves with a form in a plan near to rectangular. [List of References]