[Jared Smith]

What steel would you specify or recommend for a custom order sword intended to withstand significant test cutting?

I am considering requesting a “standard geometry” model sword in a “non standard material” from one of the more reputable manufactures. This post is not a criticism of that manufacturer. Some modern steel materials may offer higher cutting edge performance. This could possibly be higher performance than historically realistic…but still be preferred in the case of a purchase intended for heavy test cutting. These higher performing materials could also greatly increase difficulty of machining…possibly doubling costs. My desire is to purchase a sword that would normally be sold in the $500 to $800 U.S. price range, but upgrade the material choice. I would still like to keep costs below $1500 U.S. I would like to see constructive feed back on the errors I may have made below, and the practicality (costs, viability of suddenly introducing a different material, etc.) from forum manufacturers and members who actually have spent time researching tradeoffs of blade steels.

An amateur attempt at comparing two prevalent types of industry spring steels;

1075/1095 steels are fairly difficult to machine. I would expect this choice to result in high blade costs for cases of complex tapers and fullers. These materials corrode relatively fast as can be expected with plain carbon steel. I have the impression that these materials are fairly easy to temper (have read some articles and talked with knife makers about it) as they are not extremely sensitive to times during heat treatment. High toughness and high hardness are not particularly difficult to achieve with these materials, and actually start to coincide nicely around Rockwell hardness 50….generally considered o.k. for edge retention.
http://www.panix.com/~alvinj/graph1095.jpg

5160 steel material is considered one of the easiest spring steels to machinine (in the annealed state.) It reportedly has slightly better corrosion resistance than the plain carbon spring steel, although I am not sure how likely an average owner is to notice the difference. Tempering 5160 is somewhat difficult, and varies significantly with geometry (even when thicknesses are similar), requiring empirical trials to optimize. This claim is expounded upon a little lower down in this Anvil Fire web page… http://www.anvilfire.com/FAQs/heat_faq_index.htm. The heat treat process is reportedly quite sensitive to time. Unlike the 10XX series steels, 5160 impact toughness and hardness do not exhibit a simple case of convergence. “Spring grade impact toughness” increases are generally achieved at low hardness ranges (Rc 30 to 40 range… not very desirable in an edge.) I tried to find a good graph illustrating this as a function of tempering temperature, but was unsuccessful. There is a lot of discussion of this trait of 5160 steel on articles about springs however. 5160 is particularly vulnerable to Baushinger effect. This basically means it is a good spring as long as it is loaded and unloaded in one direction (such as a vehicle leaf spring.) If repeated flexed/ loaded in opposite directions its toughness and hardness break down abnormally rapidly. Warning: the following is a very large file with a long time to read and fully appreciate!
http://www.collectionscanada.ca/obj/s4/f2/dsk...Q45601.pdf
Given the range of properties that can be instilled in the material and the machining characteristics, 5160 is considered to be an optimum “value” material for quite a range of applications.

[Angus Trim]

[Jared Smith]

Thankyou for the feedback Gus.

Given your reputation for consistently producing high performing cutters, I especially appreciate the fact that you took time to share this assessment.

I had some concerns about 5160 (standard material which I believe is currently being used in many models by serveral makers) due to the fact that it appears somwhat more complex to process than simple carbon steel. With any of your established sword models, I never have had any reason for concern since results and overwhelming prefference of those who like to cut speak for themselves.

[Angus Trim]