Apron Feeder Pans

Qiming Casting’s Manganese Apron Feeder Pans Production Standard

This specification describes the requirements for manufacturing austenitic manganese steel castings for apron feeder pans. This specification gives the minimum standard that must be complied with if there are no other customers’ specifications or written instructions. We must reject materials that do not conform to this specification unless specific approval to do otherwise is received in writing from Qiming Casting. This applies at any stage of manufacture. Given reasonable notice from Qiming Casting, We must allow any customer-authorized representatives to freely enter the Qiming Casting’s works in order to expedite the work and to satisfy themselves that all tasks and inspections have been carried out according to the customer’s specification. This expediting and inspecting must not unduly interfere with the Qiming Casting’s operations, and it does not relieve the Qiming Casting of the responsibility to comply with the customer’s requirements and this specification.

Quality Control

The following requirements must be satisfied, if necessary by adding to the requirements of the customer’s existing quality system:

• Castings must be made using good modern commercial foundry practices and be sound. Any inclusions, shrinkage, or other defects must not exceed the inspection requirements in this specification.
• Manufacturing procedures must be selected to avoid the formation of detrimental phases in the structure, such as coarse grain, heavy segregation, excessive carbide phase, and excessive shrinkage.

 

Chemical Composition

1. The steel must be made either by electric arc furnace or electric induction furnace.
2. The cast analysis must conform to these limits: C 1.1-1.3%; Si 0.3-0.6%; Mn 11.5-14.5%； P ≤0.07%； S≤0.05%； Ni ≤0.4%; Cr ≤0.6%; Mo ≤0.25%; Al 0.015-0.075%
3. The deoxidation procedure must ensure that the steel contains: Si 0.30% minimum, Al 0.015-0.075%. In the last sample taken from the ladle when pouring the castings.
4. We provide a certificate of analysis. A nationally accredited laboratory must be used to do the test and issue the certificate.

 

Heat Treatment Steps

1. Step 1: Carry out the solution anneal heat treatment of the casting after it is removed from the mould and has cooled below 600℃. The casting may be knocked out hot and transferred to heat treatment immediately or left to cool in the mould or on the floor. Knock off the knock-off risers before starting the heat treatment. Full contact risers may be removed by oxy cutting, either before or after heat treatment, as required to prevent cracking. To ensure adequate quenching, remove all sand from the casting before loading the casting into the furnace.
2. Step 2：Heat to 980℃ – 1020℃ at a controlled rate to prevent cracking. Heating at 100℃ per hour is recommended. Hold for sufficient time to heat through the casting’s maximum section. Six hours minimum is required.
3. Step 3: Heat to 1050℃ – 1100℃ at any heating rate, then hold 2 – 4 hours. If the furnace is opened and part of the load is removed for quenching, the temperature must be returned to 1050℃ and held for 30 minutes before the furnace is opened again.
4. Step 4: Quench in cold water that is vigorously agitated. The water must be below 45℃ at the start of the quench, so sufficient cooling is required to make sure the water is at that starting temperature. The casting must be transferred into the water and submerged within 30 seconds of when it is removed from the furnace.

 

Mechanical Properties and Microstructure

• Make test bars of 13x20x230 mm in separate moulds and cast them at the same heat as the castings they represent. Identify the test bars by the cast on heat number. Cast enough test bars for the number of tests required, including retests.
• The test bars must be solution-annealed heat treated with the castings they represent. One test is required for each furnace heat.
• At least one test bar per heat treatment load must be bent, without machining or other surface preparation, over a former. The diameter of the former must be twice the diameter of the test bar, or in accordance with ASTM A128 Standard. Bend as fast as possible and without interruption. The test bar must bend 90 degrees without fracture. Minor surface cracking (in the de-carburized skin) up to 3 mm deep is acceptable.
• Remove a sample from a mid-radial section of the test bar, or at a distance of not less than 1.5 times the test bar diameter from the lower bar end. The sample must not show continuous or semi-continuous grain boundary carbides on more than 60% of the grain boundaries in any one field of view when examined at 500X. The sample must be metallographically prepared and etched in 3% Nital to show the grain structure.
• When the supplier has established a good correlation between heat treatment, chemical composition, successful bend tests, and acceptable microstructures, the microstructural examination may be discontinued, with the approval of Jaques. For the purposes of this clause (e), acceptable results on twenty consecutive tests are grounds for seeking this approval.
• All the pans must be passed the straightening process.

 

Internal Integrity

• Ultrasonic Testing. Ultrasonic testing of austenitic manganese steel casting is unreliable due to the large grain size and variable microstructure through the section thickness. Therefore ultrasonic testing must not be used to determine the soundness of the castings.
• Radiography. The radiographic examination must be carried out according to ASTM E186, “Standard Reference for Radiographs for Heavy Walled (51 to 114mm) Steel Castings” or ASTM E446, “Standard Reference for Radiographs for Steel Castings up to 51mm,” depending on the section thickness of the zone to be examined. The areas of the casting to be tested are shown on the component drawing. The level of acceptance for castings is Level 3.

 

Visual and Dimensional

• Surface Discontinuity Testing. All castings must be inspected visually on all surfaces (which are to be unpainted at the time of examination), and especially at changes in sections such as junctions, abutments, fillets, and web sections. The liquid penetrant test procedure ASTM E1417, “Standard Practice for Liquid Penetrant Examination,” must be used to detect surface discontinuity. Carry out the testing after grinding off all riser stubs and ingates, because these areas can be cracked by poor grinding methods.
• Surface Quality. The severity of surface defects must be judged according to the following table –based on ASTM A802, “Standard Practice for Steel Castings, Surface Acceptance Standards, Visual Examination,” surface comparators and ASTM E125, “Standard  Reference Photographs for Magnetic Particle Indications on Ferrous Castings”.
• Dimensional Tolerances. Unless specified otherwise, casting tolerances must be grade CT10 from table B1 AS1100.201 Appendix B, “Mechanical Engineering Drawing.” The tolerance listed must be halved to become a plus ( + ) or minus ( – ) tolerance. For example, a raw casting dimension of 250mm must have a tolerance of +/- 2.2mm.
• Blast Cleaning. Blast clean all surfaces that need to be machined and also surfaces where there is any sand or scale. Blast cleaning must be done either by shot or abrasive sandblasting and according to AS1627.4, “Abrasive Blast Cleaning,” Class 2.5.
• Dressing. Riser stubs must be ground to the profile of the casting; All-flash must be ground flush with the surface; All surface burn-in must be ground off; Ingates must be ground flush with the surface profile.

 

Weld Repairs

• Weld repair of castings can be considered by the supplier if options such as blending, or offering the castings as they are, would not be acceptable to Jaques. The castings must be in the solution annealed condition.
• Welding procedures and welding operators must be qualified by production and testing of test coupons according to ASTM A488, “Standard Practice for Steel Castings, Welding, Qualifications of Procedures and Personnel.”
• Defects may be excavated using arc air gouging, chipping, or by grinding. If arc air gouging is used, the casting temperature must be kept below 50℃.
• As a minimum, all preparations must be inspected for complete removal of the defect by surface testing methods. All welds must be ground back to the original profile and inspected by surface testing methods. All weld-repaired areas must be tested again, using liquid penetrant crack testing, and must comply with the inspection requirements of the casting. Radiographic testing is only required if it is specified on the drawing for the repaired area.
• Before any welds are done, the foundry must give Jaques a written weld repair procedure and get the approval of Jaques. Welds must use austenitic manganese steel filler metal, and MMAW and FCAW methods may be used. Only approved weld consumables must be used. Heat treatment is not allowed after doing a weld. Peen all welds lightly while hot, limit weld heat input to 1.0 kJ/mm maximum, and do not weave but use stringer beads only. Interface temperature must be kept below 50℃, which can be done by staggering the weld runs and cooling with water or air blast. The welds must be blended so that they are not readily apparent to the eye.
• All weld repairs must be recorded in the documentation and give a detailed description of what was done and the exact location of the repair.
• Any weld repair that goes deeper than 25% of the wall thickness of the casting must be classed as a major repair. In these instances, the details of the repair procedure, including the extent and location of the repairs by welding.

 

Inspection after Machining

Visually inspect all machined faces for clean-up and inclusions. Check all machined dimensions, in conjunction with the Inspection Record drawing (IR Drawing), and record results accurately on the IR Drawing. All the flights need to be checked on the flat jig, and there should be 2mm min. clearance between each flight.

 

Records

After finish the manganese apron feeder pans, we will share the following records for customers:

• Chemical Analysis Results
• Heat Treatment Records
• Dimension Inspection Report
• Bend Test Result and Microstructure Report
• Weld Reports
• Approval of non-compliances