SU48427A1 - The method of thermite welding rails - Google Patents

Description

An intermediate casting method for thermite welding of rails is that liquid thermite metal is poured into a hollow channel formed by refractory welding molds.

The metal, penetrating into the slot of the rail junction and melting the ends of the soles, the necks and the rail heads, welds them as they cool. In order to obtain in the slot itself and near the slotted zone of a dense, without shrink-hole casting, the metal was deposited over the rail head, forming large and high buildup.

When welding Phoenix-type (grooved) rails, the metal was also melted and completely filled the entire trench.

Removing the tide from the rolling (working) plane of the rail head and its side part (the wagon wheel flange in the Vignol rail), as well as removing metal from the Phoenix rail trough, were very difficult and costly. Thermite metal, which was welded to the rails, often went out too hard, not machinable by a chisel and a simple saw, and required grinding stones — wheels.

Under the influence of an excessively high temperature (3000–3300 °) of a thermite metal, the rail head received a burnout of its metal, as a result of which it lost its qualities in terms of resistance to wear and smothing. After an insignificant time, potholes were formed at the place of welding, and the joint, although well welded, came out of the car’s excessive impact.

The proposed intermediate casting method for thermite welding eliminates the aforementioned disadvantages. The welded joint is not only not inferior to the resistance of the whole rail, but is made even stronger by increasing the rolling surface.

In FIG. 1, 2 depict transverse and longitudinal vertical sections of a mold with a liner installed at the junction of a Phoenix-type rail; FIG. 3 is a horizontal sectional view of the mold and a top view through the slag chamber on the liner, the initial impact of a jet of liquid metal and the grooves-drains L, through which the metal flows down both sides of the liner into the channels of the seam; FIG. 4, 5, b - side view, bottom and cross-section of the liner;, FIG. 7-axonometric projection of the halves of the mold; FIG. 8-horizontal section of termite dipping.

The main and characteristic factor in the proposed method of intermediate casting welding is inserts / C (Figs. 1-6), which are installed in front of the nozzle of the casting molds on the rail head at the slot.

The liner for Vignol-type rails has an almost rectangular shape with a corresponding configuration in contact with the head. For Phoenix type (grooved) rails, the liner in its lower part has the configuration shown in FIG. 1-6.

As can be seen from FIG. 1, 2, 4-b, the insert has on the bottom plane in contact with the rail head /, the bottom of the chute Z and the small rail chute y, the hollow channel Izy with section d (Fig. 2 and 4) in the form of a sector with a chord equal to triple the width of the slit n p (Fig. 2) with a trill (height) equal to the width of the slit.

The fey channel defines the dimensions (cross-section) of the pouring around the slotted area of the head, chute and small block. Thermite enters the channel in an amount that is sufficient only to melt and weld the ends of the rails. A liner mounted over the rail joint thus prevents its tin from being eroded by metal and melted outside the dipping line.

Rail head along the entire gap

Zy is melted only a width-2 and has

a ridge elevated above the slit to a height equal to h.

In the upper part of the halves of the molds E, F (Fig. 1) are made according to the height AJ (Fig. 4), the length I {Fig. 5) and the width b (Fig. B) of the insert recess of the socket (Fig. 7). The liner fits into these sockets with a depth of .25-30 mm, on liquid clay, in order to avoid shifting it towards or floating on the surface of liquid thermite. Both halves of the form, tightly closed along the plane of their HS connector (Fig. 1), tightly grip the body of the liner.

When metal is poured into the welding form along the lateral channels, mm rises more than double the height of the rail head, forming above the liner a layer of liquid metal 20-25 mm thick. In the side channels, the metal, remaining under the layer of hot (initially also liquid) slag for a considerable time liquid, forms pressure tides, taking shrink shells and gas bubbles throughout the area of the joint between the joints below the rail rolling plane. This results in a tight casting and good welding.

When removing the form from the junction, all the metal from the plane passing through the clamps a and 6 specially made for this purpose to the level rt easily breaks off with light hammer blows.

Before zapilovka forming the ridge head above the slot, it is upset (forged) with light blows of a sledgehammer, thereby reducing its height by almost half. Then remove the minor remnants of this ridge on the level of the working rail head.

In order to prevent the metal of the rail from overheating with a very high temperature (3000–3300) thermite metal, but at the same time to ensure the melting of the surface of the rail ends in the joint, the pouring section is not made according to the semi-circle or semi-ellipsis, as in the usual intermediate casting method, shown in FIG. eight.

With this configuration of pouring, the melting of the neck and foot of the rail occurs gradually, the boundaries ad and bd increase inward, towards the axis of the joint.

In this case, in addition to the metal, pouring over and the base metal of the rail, having a greater temporary resistance to tearing, renders the resistance to fracture of the joint.

In the event of a rupture of the joint along the neck and the bottom of the rail, the destruction of this pouring pattern does not occur along the border of the pouring and the rail surface, but along the line KL, the neck gets a break inside the pouring. This indifferent at first glance causes. when the joint is broken, the safety of the carriage on it during IVs-2 months.

Both ends of the burst joint are, as it were, enclosed in a steel strong coupling, which, tightly covering the ends of the rails on all sides, will save the joint from disorder for a considerable time and sew it upon impact.

The proposed method of intermediate casting reduces by 15-20 / 0 against the usual method of consumption of thermite, and therefore the main component of thermite.