DE3248482A1 - Method of manufacturing solid-cast pin rollers according to the horizontal spin-casting principle depending upon the raw cast ball diameter and pin diameter and the casting cycles deriving therefrom - Google Patents

Abstract

With the method illustrated, a production possibility is afforded for manufacturing horizontally spun solid cast-iron pin rollers for sheet-metal and small-section production of any size. As a result of dividing up the overall mould cavity and the resulting time-lagged filling of these individual zones, the liquid contraction is purposefully influenced and the bending stress at the pin/ball transitions, which leads to heat cracks, is eliminated. Rollers made according to this method can be varied corresponding to their requirements in the range of all cast-iron qualities.

Description

Title of the invention

Process for the production of solid cast pin rollers according to the horizontal centrifugal casting principle depending on the raw ball and pin diameter and the resulting casting cycles.

Field of application of the invention The invention ensures the most economical of materials Manufacture of metallurgical tenon rolls for sheet metal and profile roll production with high wear resistance with a work layer of different thicknesses and a shatterproof bale core, including the solidly cast bearing and Drive journal.

Characteristics of the well-known technical solutions Spigot rolls produced by centrifugal casting using different processes.

These procedures differ mainly in terms of their location the centrifugal axis and - are determined by the type of centrifugal system.

The best known are: - Horizontal centrifugal casting with a rigid working axis - vertical centrifugal casting with a rigid working axis - inclined centrifugal casting with a rigid working axis arranged from 18 to 24 degrees - swiveling centrifugal casting with a movable working axis, soft from the horizontal or inclined position is brought into the vertical position during spinning.

However, all of these systems have their drawbacks, which can be found in either the high investment costs are to be sought or the production of certain dimensions exclude.

In the vertical centrifugal casting process, only rolls with one can be used Establish the roll barrel ratio of L <1, otherwise D is caused by the parabolic Surface a constant work shift is not possible.

The inclined centrifugal method has the disadvantage of being parabolic Surface largely balanced in the work shift, but due to the inclination makes an extension of the upper journal of the roller necessary.

The swiveling centrifugal casting offers good conditions for a uniform Work shift, but requires a very high level of mechanical equipment Investments. The construction and assembly services are very high.

The horizontal centrifugal process ensures a high quality of the Working shift thickness with the most favorable use of materials.

The disadvantage here is that, with increasing diameter difference, rolls Ball diameter minus pin diameter, tend to form hot cracks.

This phenomenon is supported by the shrinkage in the white solidified working layer of the bale is 1.8 S compared to the gray solidified peg material with 1 S shrinkage.

The resulting different shrinkage gap leads to a Bending stress in the area of the transition from the ball to the pin and causes cracks in the pin in the doughy state.

With larger rollers, the absolute difference in shrinkage increases and the risk of cracking continues to increase.

Object of the invention The object of the invention is to influence the Solidification process in horizontally centrifuged cast iron rollers by an interrupted one Casting sequence, combined with a necessary shape for the necessary Raw casting.

Representation of the essence of the invention The essence of the invention consists in that a raw part shape tailored to the horizontal centrifugal principle in individual casting cycles is filled.

The required quantities and casting temperatures ensure a controlled liquid iron contraction in the entire roller and thus close the Why did the tenon junctions tear out?

The different speeds "n" ensure a constant one Casting pressure in the individual metal zones.

Features of the Invention For a tenon roll, a blank shape is used manufactured (see Figure 1): D = ball diameter d = pin diameter at the pin-ball transition L = barrel length 11 = tenon length on the sprue side 12 = tenon length on the opposite side The tenon models are given a uniform draft of an angle of 1 to 3 degrees Tilt. The tenon fillets at the ball transition have a radius R of up to 25% the difference D-d 2 For rollers with an alloyed working layer, this radius may be only extend into the alloyed zone up to a quarter of the working layer thickness.

The pin length of the sprue side is in any case also with isosceles Lay out the rollers longer than the journal on the opposite side. The division of the form in the individual casting zones takes place according to the point of view of being nested cylindrical bodies each with a uniform diameter. The minor one The difference in the journal areas is neglected.

The holding time (casting interruption) between the individual zones is set up after the completion of the liquid contraction of the previous amount of iron.

The required casting temperature ensures the firm connection between the individual zones.

The rotational speed "n" for the centrifugal casting mold are calculated according to the formula certainly.

K = material-dependent coefficient of gravity d = diameter of the free surface in cm.

The individual qualities for the different zones are included freely selectable according to the intended use.

Execution example for the production of a fine iron roller with the Finished dimensions 520 x 1000 mm, total length 1950 mm and a 70 mm thick work layer a raw casting with the dimensions D = 536 p, i.e. 290, L X 10801 11 3 800, 12 = 600 total length = 2480 fixed.

The draft of the tenons is 2 degrees.

The various casting zones are divided up in the order in which they are divided 1 work shift, 2 bale core zone, 3 roller axis, 4 roller center (see fig 1).

The bale core zone does not apply to rollers with a maximum work shift 2.

The maximum working layer thickness results from the relationship D - d I 10 mm 2. The metal quantities are calculated as follows: Working layer 880 kp Bale core zone 370 kp roller axis 900 kp roller center 220 kp For the working shift, an iron with the following analysis is cast: C 3.4 - 3.6% Si 0.15 - 0.25% Mn 0.4 - 0.6% P 0.4 - 0.6% s 0.1 X Cr 1.0 - 1.5% Ni 0.5 - 0.7% Casting temperature: 16000 - 16200 K For the other zones, an iron with a uniform analysis is cast: C 3.1 - 3.3% Si 1.5 - 1.7% Mn 0.2 - 0.4% P 0.2 - 0.3% s 0.1% The holding times between the individual zones and the respective casting temperatures are: Between work shift and bale core zone 18 min casting temperature bale core zone 15000 - 15200K Between bale core zone and roller axis 10 min casting temperature roller axis 15000 - 15200K Between roller axis and roller center 15 min casting temperature roller center 14800 - 15000K For the determination of the speed "n" applies to all casting zones with a free surface, the value K = 40 K. For the roll center, 2 applies. For the diameter of the free surface, 1 center diameter is set ..

2 The resulting speeds: Work shift n t 450 bale core zone n = 500 roller axis n = 750 roller center n = 800 - blank page -

Claims (4)

Invention claims r 1. A method for the production of solid cast Trunnion rolls according to the horizontal centrifugal casting principle depending on the raw cast ball and journal diameter and the resulting casting cycles, characterized in that that an elimination of the risk of cone heat cracking by mastering the absolute Shrinkage difference between the roll barrel and the journal area is reached. 2. The method according to claim 1, characterized in that the entire Amount of liquid iron for the work shift incl. the tenon and the core area in different time stages like this is poured. that in each case before the casting of the next iron, the liquid contraction of the previously cast iron is complete. 3. The method according to claim 1, characterized in that the interior design of the raw casting is divided so that the respective casting of the intended amount of iron is only used to fill the cavity zones 1 to 4. 4. The method according to claim 1, characterized in that for implementation The following limits are required for the process: Casting temperature 1480 - 1620K holding time from 5 min to 25 min.