The three easiest pitfalls in purchasing mold steel

The three easiest pitfalls in purchasing mold steel
The three pitfalls in the procurement of mold steel are material degradation, missing flaw detection, and out of control outsourcing of heat treatment, any of which can double the lifespan of the mold.
Pit 1: Ordinary forgings emit electric slag steel
The purity of electroslag remelted steel is higher, and its price is 25% -40% higher than that of ordinary forgings. The appearance is almost indistinguishable.
The supplier only writes "H13" in the warranty, without specifying the smelting method, which is the most common vague expression.
The avoidance method is to require the furnace batch number and conduct third-party spectral retesting. The testing cost is not high, but it can screen out most of the problems.
Pit 2: Missing flaw detection report
There may be white spots, inclusions, and cracks inside the mold steel. Uninspected steel is only discovered halfway through processing, resulting in greater losses.
Ultrasonic testing shall be carried out according to standards, and the report shall include the location and level of defects.
Xinfeng Mold will require suppliers to provide inspection reports in the material procurement of wheel hub molds, corresponding to the furnace batch number.
Pit 3: Out of control outsourcing of heat treatment
Quenching and tempering are key processes that determine the lifespan. Outsourced factories may shorten insulation time or reduce tempering frequency to meet delivery deadlines.
Qualified hardness does not mean qualified organization. Molds with insufficient tempering will continue to transform and experience size drift during use.
Requesting the provision of heat treatment curves and hardness testing records is the most basic control measure.
Inspection of incoming materials
Spectral analysis confirms the brand, hardness testing confirms the status, and ultrasonic testing confirms the internal quality.
To complete the factory inspection, all three items must be done. The risk of missing internal defects still exists by only doing spectra.
Balance between price and quality
The price difference of low-priced steel often returns in terms of mold lifespan. The lifespan has decreased from 40000 mold cycles to 25000 mold cycles, resulting in losses far exceeding the material price difference.
Converting material costs by module is more reasonable than comparing prices by kilogram.
Supplier Management
Fix 2-3 steel suppliers and establish batch files. Can quickly trace batch abnormalities.
Conduct an annual supplier review, with a focus on testing capabilities and heat treatment coordination.
Approval of Material Substitution
When the customer specifies materials, written approval is required for substitution. Verbal agreement is often not recognized during acceptance.
The substitution plan should explain the performance differences and compensation measures, and cannot just write four words of equivalent materials.
Inventory and Batch
The performance of different batches of the same brand may vary. It is recommended to use the same batch of steel for important molds to reduce variability.
Inventory steel should be labeled with the date of receipt, first in first out to avoid surface decarburization caused by long-term storage.
Dispute Resolution
Disputes over material grades shall be subject to third-party testing, and the same batch of samples shall be sealed and retained before testing.
Before the steel is stored, its hardness should be measured once. If the hardness is abnormal, it indicates that the heat treatment status is incorrect. It should be isolated first and then treated.
Different parts of the same mold can use different brands. The cavity and mold base need not be forced to be consistent. It is more economical to select materials according to the force.
The storage of steel should be elevated to prevent moisture, as moisture on the ground can cause rust and pitting on the surface of the material.
Frequently Asked Questions
Question: How to distinguish electric slag steel?
Answer: Please refer to the quality assurance certificate for the smelting method and conduct spectral retesting.
Q: Is it necessary to have a flaw detection report?
Answer: It is recommended to have internal defects, as the losses will be greater in the later stage.
Q: How to control outsourcing of heat treatment?
Answer: We need to record the curve and hardness, not just the results.
Q: How many items are included in the factory inspection?
Answer: Spectroscopy, hardness, and non-destructive testing.
Q: Is low-priced steel cost-effective?
Answer: The loss of lifespan usually exceeds the material price difference.
Q: How many suppliers do you need?
Answer: It is recommended to have 2-3 companies for easy comparison and traceability.
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