GB2096918A

GB2096918A - Locating elongate specimens in quenching funnels

Info

Publication number: GB2096918A
Application number: GB8111964A
Authority: GB
Original assignee: British Steel Corp
Current assignee: British Steel Corp
Priority date: 1981-04-15
Filing date: 1981-04-15
Publication date: 1982-10-27

Abstract

Means for locating an elongate specimen 11 (e.g. a rod or wire specimen) centrally within a vertical quenching funnel 2 has an internal surface which is formed with a plurality of inwardly protruding undulations 10 of generally triangular profile. The peaks and troughs of the undulations lie respectively in parallel planes normal to the longitudinal axis of the funnel and co-operate to retain the protruding ends of a support pin 12 extending diametrically through the specimen to locate the specimen centrally within the funnel shell. <IMAGE>

Description

SPECIFICATION Apparatus for accurately locating elongate specimens This invention concerns apparatus for accurately locating an elongate specimen within a funnel type structure. The invention is especially, but not exclusively directed to such apparatus suitable for assessing the hardening response of rod and wire.

According to the present invention in one aspect, there is provided apparatus for locating a specimen centrally within a vertical funnel whose internal surface is formed with a plurality of inwardly protruding undulations of generally triangular profile, the peaks and troughs of such undulations lying respectively in parallel planes normal to the longitudinal axis of the funnel.

In one construction, the apparatus comprises an upper cylindrical shell having an inner lining whose upper rim defines an undulating ledge which co-operates to retain the protruding ends of a support pin extending diametrically through the specimen to locate the specimen centrally within the funnel shell.

According to the present invention in another aspect, there is provided an quenching funnel adapted to be upstanding within an oil bath, the funnel comprising a cylindrical shell having an internal ledge whose upper rim undulates between peaks and troughs which respectively lie in parallel planes normal to the longitudinal axis of the funnel.

The invention will now be described by way of example with reference to the accompanying diagrammatic drawings, in which: Figure 1 is a cross-sectionai view taken through apparatus in accordance with the invention; and Figure 2 is a perspective view of a detail of the apparatus illustrated in Figure 1.

The illustrated apparatus comprises a quenching funnel suitable for assessing the hardening response of rod and wire specimens discharged from a heating furnace located above the mouth of the funnel. The quenching funnel comprises a converging mouth 1, which tapers to a cylindrical shell 2 havng an inner lining 3 attached to the shell 2 by set screws 4. The shell 2 is a sliding fit over the upper end of a nozzle 5 of inverted "T" configuration. The nozzle 5 is formed with a converging upper section 6 and is connected through one of its lower ends into an oil line 7 which is in turn connected to a pump (not shown). The nozzle end remote from the pump is closed-off by a blanking cap 8.

The upper rim 9 of the lining 3 forms a ledge whose surface undulates between a series of uniform peaks and troughs to form a crenelation 10 of generally triangular profile. The crenelated end of the lining 3 is illustrated in perspective view in Figure 2. Typically, four or six crenelations 10 would be provided each having a rounded top and each tapering in thickness to a minimum at its extremity.

The angles A and B at the major changes in section within the funnel and the nozzle are selected to minimise turbulence in tne oil stream flowing through the funnel.

A bar specimen 11 is shown suspended within the funnel in Figure 1. The specimen is simply cut to the required length and drilled at one end to accommodate a transverse support pin 1 2 passing diametrically through the specimen. The hole is drilled to provide an interference fit for the pin 12, the protruding ends of which are used to locate and suspend the specimen within the funnel.

The funnel shell 2 and the lining 3 may be perforated to allow oil to flow into contact with the specimen. These perforations may be in addition to or instead of the pump used to induce an upward oil flow through the funnel.

The quenching funnel has especial application in assessing the hardening response of rod and wire of less than approximately 25 mm diameter under standardised and controlled conditions. For such an assessment, a specimen is conveniently heated for a set period of time within a sealed vertical tube furnace previously flushed with a protective atmosphere selected to minimise surface oxidation of the specimen. For steel specimens an atmosphere containing 95% nitrogen and 5% hydrogen has been found to be suitable.

A quenching furnace is conveniently mounted on a trolley and rail system which allows correct positioning of the furnace door over the mouth of the quenching funnel. The funnel is located vertically within a tank filled with oil maintained at a predetermined temperature by for example an immersion heater and to a level which is just below the upper rim of the funnel mouth. The pump connected to the nozzle 5 operates to produce a controlled oil flow upwardly through the funnel interior.

After a set period of time the furnace door is opened and a specimen released from the tube furnace. The specimen falls vertically into the funnel mouth 1 and as it enters the lining 3 its support pin 12 engages the undulating lining rim and settles between opposite troughs of the crenelations 10 thereby centering and aligning the specimen within the funnel. The undulating rim of the lining ensures correct and reproducible alignment of specimens to be assessed.

From the foregoing it will be understood that apparatus in accordance with the invention is especially suitable for use with quenching units for assessing the hardening response of rod and wire specimens in standard reproducible and controlled conditions. Such assessments are important as quality control checks to ensure that feedstock is capable of achieving desired strength levels. The specimens may be of iron or steel or non-ferrous metals and alloys.

It is also to be understood that the apparatus can be used in any situation where it is necessary consistently to locate a specimen whether metallic or non-metallic accurately for assessment or other purposes.

Claims

1. Apparatus for locating a specimen centrally within a vertical funnel whose internal surface is formed with a plurality of inwardly protruding undulations of generally triangular profile, the peaks and troughs of such undulations lying respectively in parallel planes normal to the longitudinal axis of the funnel.

2. Apparatus as claimed in Claim 1 comprising an upper cylindrical shell having an inner lining whose upper rim defines an undulating ledge which co-operates to retain the protruding ends of a support pin extending diametrically through the specimen to locate the specimen centrally within the funnel shell.

3. Apparatus as claimed in Claim 2 the vertical funnel has a converging mouth which tapers to the cylindrical shell to which the inner lining is attached.

4. Apparatus as claimed in Claim 2 or Claim 3 wherein the funnel shell and the lining is perforated to allow a coolant to flow into contact with a specimen located within the apparatus.

5. A quenching funnel adapted to be upstanding within an oil bath, the funnel comprising a cylindrical shell having an internal ledge whose upper rim undulates between peaks and troughs which respectively lie in parallel planes normal to the longitudinal axis of the funnel.

6. Apparatus for locating a specimen substantially as herein described with reference to Figures 1 and 2 of the accompanying drawings.