CA1334834C - Container corner - Google Patents

Abstract

The invention relates to a corner element for containers, made of manganese steel, fitted with joining holes on its three outer sides. It is made of a steel-plate having a Mn : C ratio of 8 to 12, a (P+S) content of max. 0.04 percent by mass and a C-content of max. 0.2 percent by mass. The corner element is assembled from shell elements shaped by cold-working of the steel-plate and from distance inserts by welding.
The size and tolerance values of the corner element meet even the strictest specifications. Its mass is at least 10 percent smaller than that of its steel--cast counterpart. It needs hardly any remachining and its replacement inside the container can be simply and quickly performed.

Description

- The present invention relates to a manganese steel corner element with joining holes on its three outer sides.
Different types of containers which are categorized by the ISO standards according to size (10 to 40 feet length) and load capacity (10, 20, 24 and 30 Mp) are used for transporting piece goods, bulk goods, liquids, etc.
The corner elements are placed at the 8 corners of containers, facilitating their being elevated or joined together or joined to the transporting vehicle either horizontally or vertically. The corner elements are connected by vertical and horizontal holders made of rolled plates or profile forms. In addition to their movability, elevating and fastening, it is important that containers can be stacked on each other.
According to the traditional technical methods applied so far, corner elements have been steel-cast by container manufacturers, and the finished castings are usually welded manually or on a low mechanization level to the vertical and horizontal holders. Checking the welds is awkward and not entirely safe. Among the possible failures of containers, beside the breakage of corner elements, seam rips or breaks have been quite common owing to defective welding. When it comes to repairs (e.g. a broken corner element needing to be replaced) the maintenance of the original sizes and clearances is difficult and requires much time and energy. Besides, users are forced to withdraw the defective containers from operation for a long time.
In the October, 1985 issue of the scientific review Cargo Systems P. Hewitt reports on tests concerning cast corners, carried out by Sea Containers in cooperation with the research laboratory Iron and Steel Co. and the Trade Association Sheffield company. The examinations included different measurements and tests on cast corners - 1- .~

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- made in different countries all over the world. The results as regards Charpy's impact energy at low temperature are set out in the following table.

Impact energy Temperature (average of 3 Manufacturer measurements) C
A 4.0 J -40 B 7.5 J -40 C 14.5 J -40 D 10.5 J -40 A suitable material for manufacturing corner elements must meet the specification of IS0 1496/1 and/or LR 1984, where the required values at -40C, at a "V" slot and with Charpy's method are the following:
on a 10 x 10 mm test bar min. 34 J
10 x 7.5 mm test bar min. 28 J
10 x 5 mm test bar min. 23 J
The table shows that these requirements are met by none of the manufacturers listed. This led to the perception that one of the defects of cast corners manufactured with the present state of technical knowledge is the unsatisfactory value of impact energy at low temperatures.
A British company called Blair has recently developed a corner element that after a single normalizing heat-treatment and at -50C provides an impact energy value of KVmjn= 21 J. However, it is not at low temperatures that most breakages of corner element occur. In fact, according to data supplied by large railway companies (such as the West German DB, the French SNCF or the British BR) damage to corner elements or seam rips of their holders takes place in the positive temperature range owing to rough -- 3 ~ 1 33~ 8~ ~

elements must meet the specification of IS0 1496/1 and/or LR 1984, where the required values at -40 C, at a "V" slot and with Charpy's method are the following:
on a 10 x 10 mm test bar min. 34 J
10 x 7.5 mm test bar min. 28 J
10 x 5 mm test bar min. 23 J
The table shows that these requirements are met by neither of the manufacturers listed. This led to the perception that one of the defects of cast corners manufactured at the present state of technical knowledge is the unsatisfactory value of impact energy at low temperatures.
A British company called Blair has recently developed a corner element that after a single normaliz-ing heat-treatment and at -50 C amounts to the impact energy value of KVmin= 21 J. However, it is not at low temperatures that most breakages of corner element occur.
In fact, according to data supplied by big railway companies (such as the West German DB, the French SNCF
or the British BR) the damage of corner elements or the seam rips of their holders take place in the positive temperature range owing to rough handling and reloading as well as in the course of shunting and marshalling of railway wagons.
Owing to the material composition of steel castings and the additional dynamic stress due to rough handling, their mechanical qualities get poorer in the negative temperature range. All these result in cracks due to the casting technology corner elements weigh too much;
the 8 corner elements required for each container can be manufactured only in four patterns, shaped and cast separately.
It follows from the foregoing that to manufacture the corner elements in accordance with the specifications is not easy.
It is an object of the invention to eliminate the disadvantages of the known method and to provide a new type of corner element that is suitable for serial production regarding material, structure and technology, is economical of energy and does not require repeated heat treatment, is suitable for being stacked, and has an impact energy at low temperature in accordance with the specifications.
Accordingly, the invention provides a corner element for a container, made of manganese steel, with joining holes on its three outer sides, characterized by being made of a steel-plate having a Mn:C ratio of 8 to 12, a total phosphorus plus sulphur (P+S) content of a maximum of 0.04 percent by mass and a carbon content of a maximum of 0.2 percent by mass.
The material of steel-plates of this composition is homogeneous, it has pliable edges (Rmjn= a/2 mm, wherein "a" stands for the plate thickness) and its impact energy value (KVmin) at -40C amounts to 21 J. The wall thickness of the corner elements made of such material will be smaller than that of a casting, thus it is advisable to arrange distance inserts on the inner sides of the joining holes, thereby ensuring proper connection with fastening elements.
The steel-plate that serves as the basic material of the corner element according to the invention is of - homogeneous granular structure even in a direction perpendicular to the direction of rolling, and is suitable for applying cold-working technology. Its elongation value (~) is over 22 percent and its edges are quite pliable.
The sizes and degrees of tolerance of the corner elements made of such a material meet even the strictest specifications (e.g. ISO 1161). The mass of these corner elements is at least 10 percent less than that of their steel-cast counterparts and its dispersion is 2 percent less than the rated value. They require hardly any remachining and can be replaced within the container simply and quickly. The individual stages of their manufacture can be mechanized to a high degree, so robotization is also applicable, enabling high precision and reproducibility of production.
The production of the corner element can be based on the cold-working technology which is simpler and of low energy consumption. The plates cut (pressed) are bent and assembled as cold. The welding of the elements can be carried out by robots horizontally, by simple geometrical tracing. The root of weld is fixed and welding is reproducible with high precision. The finished product does not require any further heat-treatment and the technology of its replacement is much simpler.
Two embodiments of assembly of the corner element according to the invention are shown in Figures 1 to 7. In the second embodiment the six sides of the corner element are formed from two trilateral shell elements the sides of which are joined along three edges and together form one common peak, while the sides of the shell elements of the first embodiment are joined along two edges, and the shell elements are generally U-shaped.
In the drawings:
Figure 1 shows the top and side views of embodiment 2 of the corner element and its section along line D-E;

Figure 2 represents a blank of the shell element "A" of embodiment 2;
Figure 3 shows a blank of the shell element "B"
of embodiment 2;
5Figure 4 shows shell elements "A" and "B" of embodiment 2 together with their distance inserts;
Figure 5 shows the distance inserts C1 and C2 of embodiment 2 and a blank from which inserts C3 may be cut;
Figure 6 represents the corner element assembled from shell elements "A" and "B" and the distance inserts of version l; and Figure 7 shows the exploded view of version 2 of the corner element according to the invention, wherein "A"
and "B" are the two shell elements, C1, C2 and C4 are the distance inserts and the lines h-h represent the bending edges.
The corner elements arranged in the upper and lower planes of the container differ only in respect of the sizes of the holes on their shorter sides; therefore, the shell elements "A" are manufactured with two different holes. The shell elements "B" are identical in the upper and lower rows and are shaped in such a way that they form the corner element together with their counterparts "A".
The shell element "A" with a slight modification can be considered a finished product as it can serve as the corner element of tank containers.
The size and tolerance values of the corner element represented in Figures 1 to 7 meet the 1984 specifications of IS0 1161, and are as follows:
30length 1 = 178 + 1 mm width w = 162 + 1 mm height h = 118 + 1 mm mass 9.60 - 9.75 kg + 2 %
The corner elements are interchangeable, besides they can be manufactured in a range of dimensions for repair purposes.

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According to embodiment 1 the corner element consists of a shell element "A" made of a 10 mm thick plate bent to form a "U" profile with an inner bending radius of Rmin= a/2 mm, and of a shell element "B" made of a 8 mm thick plate to form an "L" profile with an inner, bending radius of Rmin= a/2 mm. The suitable holes are on the shell element "A", while on the shell element "B" there are no holes at all. The distance inserts C1, C2 and C4 of the shell elements "A" of corners in the lower row are seated at the inner side of the holes, their position is defined by an orienting gauge. On the shell elements "A" of corners in the upper row there are distance inserts marked C2, C3 and C4 .
By defining the hole size on the shell element "A" it can be determined whether the corner element should be placed on the upper or lower part of the container. The mirror image of a shell element can be produced either by bending the blank from which an element is made in the opposite direction or by inverting the blank.
The spare parts listed above are assembled in the orienting gauge and, having checked the size, are fixed by tack welds. The next operation is the continuous welding of single-fillet welds.
The last phase is the working of the inlet slopes (6 x 45) at the outer side of the holes.
When the corner elements are finished, their surface cleaning takes place.
Embodiment 2 is also based on the conception that corner elements should be constructed by two shell elements and three distance inserts. Shell element "A" has a hole on each side. They are cut out of a flat sheet before bending. Shell element "B" has no holes. The two shell elements are assembled to construct the corner element in the same way as described for embodiment 1 (see Figure 7).

corner element according to the invention, wherein A and B are the two shell elements, Cl, C2 and C4 are the distance inserts and the lines h-h represent the bending edges.
The corner elements arranged in the upper and lower planes of the container differ only in respect of the sizes of the holes on their shorter sides; therefore, the shell elements "A" are manufactured with two different holes. The shell elements "B" are identical in the upper and lower rows and are shaped in such a way that they form the corner element together with their counterparts "A".
The shell element "A" with a slight modification can be considered a finished product as it can serve as the corner element of tank containers.
The size and tolerance values of the corner element represented in Figs. 1 to 6 meet the 1984 specifications of IS0 1161. Thus its - length is 1 = 178 + 1 mm - width is w = 162 - 1 mm - height is h = 118 + 1 mm - mass is 9.60 - 9.75 kg + 2 %
(according to version.) The corner elements are interchangeable, besides they can be manufactured in gradual dimensions for repair purposes.
According to version 1 the corner element consists of a shell element "A" made of a 10 mm thick plate bent to form a "U" profile with an inner bending radius of Rmin= a/2 mm, and of a shell element "B" made of a 8 mm thick plate to form an "L" profile with an inner, bending radius of Rmin= a/2 mm. The suitable holes are on the shell element A, whlle on the shell element "B"
there are no holes at all.
The distance inserts Cl, C2 and C4 of the shell elements A of corners in the lower row are seated at the inner side of the holes, their position is defined by an orienting gauge. On the shell elements A of corners in the upper row there are distance inserts marked C2, C3 and C4.
By defining the hole size on the shell element A
it is determined that the corner element should be placed on the upper or lower part of the container. The mirror image of the shell element can be produced either by changing the bending direction to the opposite or by the inversion of the plate.
The spare parts listed above are assembled in the orienting gauge and, having checked the size, are fixed by tack welds. The next operation is the continuous welding of single-fillet welds.
The last phase is the working of the inlet slopes (6 x 45) at the outer side of the holes.
When the corner elements are finished, their surface cleaning takes place.
Version 2 is also based on the conception that corner elements should be constructed by two shell elements and three distance inserts. Shell element "A"
has a hole on each side. They are cut out of the out-spread plate before bending. Shell element "B" has no holes. The two shell elements a.e assembled to construct the corner element in the same way as described for version 1.

Claims (3)

1. Corner element for a container, made of manganese steel, with joining holes on its three outer sides, characterized by being made of a steel-plate having a Mn:C ratio of 8 to 12, a total phosphorus plus sulphur (P+S) content of a maximum of 0.04 percent by mass and a carbon content of a maximum of 0.2 percent by mass.

2. Corner element as claimed in claim 1, wherein the element is assembled by welding from shell elements produced by cold-working of the steel-plate.

3. Corner element as claimed in claim 2, wherein the shell elements are made by bending or pressing or by bending and pressing.