yes, re-heat could make it worse. practically i agree with what Ed suggests to prohibit re-heat to re-use. My previous opinion was more of theoretical[bigears]
Macro cracks/voids are unlikely to be eliminated. micro fatigue cracks (unlike corrosion cracks) can be potentially healed by heat treatment.
1. stress relief, can help to reduce the likelihood of further cracking.
2. Fatigue cracking can create grain boundaries that are not aligned properly...
Like genetic austenitic stainless, this alloy is considered "not heat treatable", Q&T is unlikely to get you martensite. However, some sorts of heat treatment may get you a smaller grain size, which can bring you a higher yield strength per the Hall-Petch relationship. otherwise you will need...
Mike offered a simple, practical approach to measure Br, but it is under quite a few conditions: 1. it is for high coercivity magnet, with close to rectangular/square hysteresis loop. 2. two poles, magnetized straight through, 3. consistent cross-section.
using HH coils, or a single search...
so sounds like you wanted some dirty and cheap soft magnetic material. try any low carbon steels 1002, 1005, 1008, 1010 ...whatever you can find. keep in mind, carbon very much affects permeability, the less the better. also do a stress relief anneal if material experienced significant...
if the last deforming temp and reduction are the same I do not see much difference on mechanical properties. hte big difference is rolling is one dimensional (only increasing length no much on width), while forge is two dimensional, and so a forged bar is more uniform in micros and mechanicals.
Technically (not representative of a quality engineer) 718 can and is being used for oil & gas applications still meeting the maximum hardness requirements of the NACE, but normally with less Nb addition and a higher temperature heat treatment for a better corrosion and a bit compromised strength.
Remelting scrap sheet metal apparently no issue
melting iron and silicon powder could have issue. using VIM for example the powder could have magnetic coupling issue. Limiting the addition of powder amount within 50% could solve the problem. but why you need powder, why not buy some Fe and Si...
have you ever "seen" MnS, or just speculate based on high Mn and S contents from EDX? if the former, are they taken a form of elongated inclusions? MnS can act as macro-voids or micro-cracks. MnS inclusions can also promote HIC. If all these are true, it seems to me cracks initiate around the...
Noticed lots of people were confused with "mechanical" stress relief (myself was not excluded at the beginning) given that the mechanical cold work would induce working harden leading to a higher strength.
In this case, the cyclic loading did the opposite: stress relief.
Basically the cycle...
seems to me Naval brass C464. ASTM B21.
Other grades with similar Zn content are C462, C268.
not sure what role it is for 0.1% Nb, prossibly to improve mechanical or corrosion resistance.
c464 is hard to form a single alpha solid solution alloy, but rather a two-phase alpha+beta. beta...
There is no universally accepted equation that directly relates toughness to CE for 4140. However, in general, an increase in CE can lead to a decrease in toughness, while increase in hardness and strength. any specific reason why your HT supplier says the opposite? perhaps they are concerning...
16th century? this is ancient metallurgy! ancient China, India and Middle East, people used smelting process with iron ore and silica, and added coke as heat source and reducing agent to make Fe-Si alloy. similar to cast iron. Si increase fluidity, decrease melting temp. while mechanically...
@OP: are you looking at M-H curves which will never be "saturated" (flatten)? you need to convert to B-H to subtract the external H effect. From what I saw with austenitic stainless, they are easily to be saturated.
magnetic induction tends to increase as temp decreases due to decrease in...
Strain induced martensitic transformation in austenitic stainless causes ferromagnetic. There are also thermal expansion alloys undergo a martensitic phase transformation leading to anomaly CTE. These are pretty well documented, and this often happens above liquid N2 temp. it is interested to...
5 Tesla, 5 Kelvin are pretty typical SQUID unit in many university labs, 14-16 T is very rare in Commerical. Florida high magnetic field has all kinds of high fields, DC up to 20T for all purpose, 32T for HTS materials. pulsed field can be over 100T. temp can reach 0.02 K.
curious about what are...
yes, there is appreciable difference. VIM/VAR or VIM/ESR 304 is cleaner than regularly melted 304. i had customers ordered both VIM/VAR and VIM/ESR 304 for medical and watch applications asking for least inclusions to control polish process (watch) and implant (medical).
Interestingly, VIM/ESR...
Forget the name(s) of the spec, pretty sure i saw something min UTS 180ksi for full hard, >200ksi extra hard. 125ksi is kinda 1/2 hard. When the material goes to full, extra hard, the EL becomes very low, and YS is also high close to UTS.
There does not exist a size cutoff between bar and...
Why do you need data from all 4 quadrants? if material is saturated, loop will be symmetric,1-2 quadrants should be enough.
RE magnet is unlikely able to saturate with a hysteresisgraph with a non-symmetric loop. you can try run a small piece in a VSM (up to 2T) or a SQUID (up to 5T), then...
