Mr. Chen asked: “We are cutting 1mm-thick magnesium alloy profiles for solar photovoltaic products. Currently, we are using P20 mold steel, but the cutting edge wears out after only about 3,000 cuts. What type of tool steel should we use?”
The cutting edge of a solar PV panel cutter is very thin and requires extremely high toughness; in other words, the die steel must possess both high hardness and high toughness. Otherwise, the cutting edge is prone to chipping or cracking. The main problem users currently face is that if the hardness is too high, the edge cracks; if it is too low, the edge collapses. A short service life is the inevitable result.
P20 is a 3Cr2Mo low-alloy steel with a hardness of 33 HRC. While it offers good toughness, its strength is insufficient, making the cutting edge prone to wear and chipping.
Mr. Chen added that they are currently using this inexpensive steel because the cutting blades are prone to cracking and wear out quickly. However, with six production lines, the blades need to be replaced after just 3,000 cuts, which is extremely cumbersome. Furthermore, the blades wear out quickly, so they are urgently in need of a tough tool steel to extend the cutting edge’s service life.
When cutting solar PV profiles, they have previously used H13, 8407, 8418, spring steel, DC53, 8566 (four-fold), Cr12MoV, SKH51, PM23… and other common mold steel grades. They’ve tried them all, and the common fate was that the harder ones chipped, while the softer ones suffered corner collapse. But this is the first time I’ve heard of using P20 for cutting blades. It seems this customer was truly backed into a corner and had no other options—they’re just grabbing whatever they can find. It’s a case of grasping at straws.
In the past, our customers have used high-toughness LG die steel for the cutting edges of profile cutters. LG has 8 to 9 times the toughness of DC53, with a hardness of 54–58HRC. It is so tough that it won’t break even if bent by hand. Based on customer testing, there is currently no better option than LG.