When you can’t shoot a video, come take a walk around the workshop—you’ll have something to say.
I saw four pieces of 1.5-metric-ton batches of high-quality 8433 heat-resistant steel ready for shipment, and I just wanted to tell you that the heat resistance and stability of 8433 are 2–3 times that of H13, with a hardness of 50–54 HRC. It won’t lose its hardness through annealing over its service life. What’s especially worth emphasizing is that even if you repair the mold until it’s worn out, the hardness on the back side won’t decrease.
A customer who hot-forges stainless steel swords mentioned that using heat-resistant steel 8433 for hot-forged stainless steel results in a longer service life than H13 and is more cost-effective.
He specializes in hot-forged stainless steel swords, which essentially involves hot-flattening. Sword products have strict dimensional requirements, and previously, using H13 resulted in a service life that was simply too short. Now, with heat-resistant steel 8433, the mold life has effectively doubled. After optimizing both the mold and the equipment—and increasing the hot forging stroke speed—the mold life has improved even further. Currently, when using 8433 to hot-forge 316 stainless steel swords, the mold only requires a full surface reduction after producing 5,000 units, and each reduction of just 4–5 mm is sufficient to remove the softened layer.
Because H13 has such poor heat resistance, its overall hardness decreases. If a new die can produce 1,000 pieces, after one surface reduction it can only produce 600; after another reduction, the die loses its overall hardness, and the mirror finish becomes meaningless. However, with 8433, each surface reduction of just 4–5 mm removes the softened layer, and the mold still maintains a lifespan of 5,000 cycles. When calculated this way, the cost of 8433 molds is actually lower; I need to repair them less frequently. Furthermore, for molds of the same height, 8433 allows for more repair cycles, resulting in a longer overall mold lifespan.
Let me remind you: die collapse in hot forging is not caused by low hardness, but because the die has been annealed—it has lost its hardness and red hardness, which naturally leads to collapse and cracking. Simply increasing the die’s hardness is useless; you must find a way to improve the heat resistance of the die steel to solve the collapse problem.
If your hot-forging dies, which originally used H13, were collapsing too quickly, you can switch to the heat-resistant steel 8433. Its heat resistance and stability are 2–3 times that of H13, and it won’t anneal out. Only then will your die’s hardness remain stable—this is the fundamental guarantee against die collapse.
On this basis, higher hardness translates to better resistance to thermal wear, making the die less susceptible to wear and extending its service life. Since your die won’t be completely annealed, it can be repaired more times; simply reducing the working surface by 4–5 mm restores the die’s service life—this is the advantage of 8433 heat-resistant steel.
Take this client of mine, for example. He hot-forges 316 stainless steel, and with each face-reduction of just 4–5 mm, the softened layer is removed, leaving the die as durable as a new one. This is unlike H13 die steel, where each face-reduction cuts the service life in half—and after a few reductions, further use becomes pointless.
If your hot-work dies made from H13 are wearing out too quickly and you want to extend their service life, heat-resistant steel 8433 is definitely worth a try.
When it comes to hot-forging dies suffering from wear and cracking, using 8433 die steel is even more satisfying than eating braised pork.
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Wu Dejian’s tool steel, the chief of staff of the user, bought everything he had used.