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Lucrator metalurgie- Cromare

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14 replies to this topic

#1
Jericho22

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Buna seara,dupa cum spune si titlul,am primit o oferta de munca ca operator pe o masina de cromare. Din cate am inteles e cam toxic. As vrea sa stiu parerile voastre si daca e cineva care a mai lucrat pe asa ceva..

#2
baribalu

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Evita.... daca tii la sanatatea ta..

#3
Onan_Barbaru

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Daca o sa porti echipamentul de protectie adecvat si n-o sa lucrezi precum Doreii in slapi si maieu, nu-i nici o problema.

#4
honeymik

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Ai ceva cunostinte in domeniu, salariul merita? In ce domeniu?
Iar daca vorbim de cromare, este vorba de cuve/bazine cu diferite substante, nu "masina". Si de obicei procesul este minim semi-automat.

Edited by honeymik, 19 March 2018 - 19:03.


#5
Jericho22

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 honeymik, on 19 martie 2018 - 19:03, said:

Ai ceva cunostinte in domeniu, salariul merita? In ce domeniu?
Iar daca vorbim de cromare, este vorba de cuve/bazine cu diferite substante, nu "masina". Si de obicei procesul este minim semi-automat.

Tot ce stiu e ca se fac bare si tevi ca alea de balustrada. Angajatorul mi a spus ca o sa lucrez pe o masina de cromare automatizata..Acum..mai multe nu stiu

#6
honeymik

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Mergi la interviu, daca este posibil solicita sa vezi hala cu linia respectiva de cromare, o sa iti faci o idee despre conditiile de munca.
Inainte sa mergi la interviu informeaza-te de pe google cu privire la procesul de cromare.

Edited by honeymik, 19 March 2018 - 19:11.


#7
myshyk

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 honeymik, on 19 martie 2018 - 19:03, said:

Ai ceva cunostinte in domeniu, salariul merita? In ce domeniu?
Iar daca vorbim de cromare, este vorba de cuve/bazine cu diferite substante, nu "masina". Si de obicei procesul este minim semi-automat.
Inseamna ca n-ai vazut/auzit  in viata ta de masina de trovalizat.. E o metoda folosita de foarte multi ani, eu am auzit de ea in ´80, dar de vazut, am vazut-o prima data in ´90 in Germania,. Masina asta stie sa debavureze piese de dimensiuni mici si medii, face tratamente chimice de suprafata anti oxidare si , cromeaza piesele prin vibrare, folosind pasta cu continut de crom. Nu se elimina noxe de nici un fel.
N-am timp sa caut mai adanc, dar in principiu, cam asta este:
http://www.mbtrading...t-vibrofinisat/

Edited by myshyk, 19 March 2018 - 20:01.


#8
r_murphy

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 myshyk, on 19 martie 2018 - 19:58, said:

cromeaza piesele prin vibrare, folosind pasta cu continut de crom.

imi dai voie sa fiu sceptic in ceeace priveste veridicitatea acestei afirmatii? intr-adevar, nu sunt la curent chiar cu "cele mai noi cuceriri ale stiintei si tehnicii, ale cunoasterii umane, in general"  si nici procesul de cromare electrochimica nu il cunosc amanuntit, dar stiu ca implica o sumedenie de procese de pregatire a suprafetei si mai ales o foarte atenta urmarire a depunerii, altfel iesea suprafata ca naiba si dadeau piesele la "rebute" .. practic, dintre toate acoperirile galvanice care se faceau, cromarea era cea mai pacatoasa si care implica cele mai toxice substante (saruri de crom?).

@ initiator - du-te si vezi despre ce este vorba, suna cam anapoda termenul ala de masina de cromare, asa cum am scris, "pe vremuri" cromarea se facea electrochimic (bai cu substante si curenti electrici care treceau prin respectivele piese).

ma gindii o lecutza si-mi veni in minte ceva .. daca ar exista masinaria aia fenomenala, oare de ce pe triscovery, la documentarele alea cu restaurarile de masini, vazui ca tot electrochimic au (re)cromat piesele de ornament de la masini?!?!?

#9
myshyk

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Nu e o inventie noua, asa cum am scris, am auzit de ea la scoala de maistri in ´80. In ´90 , am ajuns sa lucrez in Germania, la o firma care pregatea instrumentar chirurgical, pense, pensete, chestii din acestea marunte. Piesele debitate, (mentionez ca pensetele erau deja sudate in puncte) se bagau intr-o cuva rotunda, pe arcuri( ca aceea din poza din link)care executa o miscare de rotatie si in acelasi timp era vibrata. Impreuna cu piesele, se bagau si niste pietricele abrazive,, iar pentru ca in procesul de debavurare se degaja caldura, se racea interiorul in permanenta cu apa. Dupa debavurare, se schimba materialul abraziv cu altul mai fin si in acelasi timp, se adaugau in cuva solutii de protectie a suprafetelor impotriva oxidarii, Dupa acest ciclu, piesele erau scoase si cufundate intr-o baie de neutralizare, dupa care erau reintroduse in cuva, inpreuna cu niste pietricele specifice, in forma de fus, adaugandu-se  si acea pasta care continea crom. Rezultatul erau niste pensete sau piese ca acelea pe care le baga medicii pe limba cu "casca gura mare, zii aaaa"(imi scapa numele, parca spatule) cromat cu un strat egal si rezistent de crom,  obtinut prin baterea pastei pe suprafata metalica. Tot acolo se introduceau si o serie de repere din aluminiu, de la ceva pompe de injectie, care erau debavurate si tratate chimic anti oxidare.  Asa ca, cromare si nichelarea se pot face si prin mijloace chimico-mecanice, nu doar prin metode electro-chimice. Asta voiam de fapt sa subliniez, nu sa ma arat cat de multe stiu eu  despre....
Culmea e, ca inainte de asta, am avut tangenta cu cineva de la o cooperativa din Timisoara, care slefuia si finisa jumatati de pensete medicale pentru a fi sudate si nichelate. Era o operatie greoaie de slefuire manuala a fiecare bucati in parte, de-i sareau capacele slefuitorului pana le debavura si mai apoi le finisa schimband discul de slefuit cu unul de finisat.Dupa care mergeau la sudat si mai apoi la cromat dur si ultima data la nichelat.
Cat despre de ce nu se folosesc si la masini, sa stii ca o parte din elementele cromate ale masinilor, clantele spre exemplu se cromeaza cu aceast metoda. Mai exista si metode de cromare electrochimica in tambur, care e folosita tot la piese cu marime relativ mica.In rest, ornamentele mari si cele din table subtiri, trec prinm metoda calasica  a depunerilor electro-cnimice.

#10
Assur

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Cromul hexavalent e cancerigen...lasa-i naibii, gasesti un alt job, fara sa platesti cu sanatea/viata ta.

Quote

Biological role

Main article: Chromium deficiency
In the form trivalent chromium, Cr(III), or Cr3+, chromium was identified as an essential nutrient in the late 1950s and later accepted as a trace element for its roles in the action of insulin, a hormone critical to the metabolism and storage of carbohydrate, fat and protein.[6][55] The precise mechanism of its actions in the body, however, have not been fully defined, leaving in question whether chromium is essential for healthy people.[6][56][57][58]
Trivalent chromium occurs in trace amounts in foods, wine and water.[6][59] In contrast, hexavalent chromium (Cr(VI) or Cr6+) is highly toxic and mutagenic when inhaled.[60] Ingestion of chromium(VI) in water has been linked to stomach tumors, and it may also cause allergic contact dermatitis (ACD).[61]
Chromium deficiency, involving a lack of Cr(III) in the body, or perhaps some complex of it, such as glucose tolerance factor is controversial.[6] Some studies suggest that the biologically active form of chromium (III) in an oligopeptide called low-molecular-weight chromium-binding substance (LMWCr), which might play a role in the insulin signaling pathway.[62]
Although the mechanism in biological roles for chromium is unclear, dietary supplements for chromium include chromium(III) picolinate, chromium(III) polynicotinate, and related materials.[6] The benefit of supplements has not been proven.[6][63]
In the United States, the dietary guidelines for daily chromium intake were lowered in 2001 from 50–200 µg for an adult to 35 µg (adult male) and to 25 µg (adult female).[6][64] In 2014, the European Food Safety Authority published a report stating that the intake of chromium(III) has no beneficial effect on healthy people, thus the Panel removed chromium from the list of nutrients and essential elements.[62][56]
Chromium content of common foods is generally low (1-13 micrograms per serving).[6][65] Chromium content of food varies widely due to differences in soil mineral content, growing season, plant cultivar, and contamination during processing.[65] In addition, large amounts of chromium (and nickel) leach into food cooked in stainless steel.[66][67]
Dietary recommendations

The U.S. Institute of Medicine (IOM) updated Estimated Average Requirements (EARs) and Recommended Dietary Allowances (RDAs) for chromium in 2001. For chromium there was not sufficient information to set EARs and RDAs, so needs are described as estimates for Adequate Intakes (AIs). The current AIs for chromium for women ages 14 and up is 25 μg/day up to age 50 and 20 μg/day for older. AI for pregnancy is 30 μg/day. AI for lactation is 45 μg/day. For men ages 14 and up 35 μg/day up to age 50 and 30 μg/day for older. For infants to children ages 1–13 years the AI increases with age from 0.2 to 25 μg/day. As for safety, the IOM sets tolerable upper intake levels (ULs) for vitamins and minerals when evidence is sufficient. In the case of chromium there is not yet enough information and hence no UL. Collectively the EARs, RDAs, AIs and ULs are referred to as Dietary Reference Intakes (DRIs).[68]
The European Food Safety Authority (EFSA) refers to the collective set of information as Dietary Reference Values, with Population Reference Intake (PRI) instead of RDA, and Average Requirement instead of EAR. AI and UL defined the same as in United States. The EFSA does not consider chromium to be an essential nutrient, and so has not set PRIs, AIs or ULs. Chromium is the only mineral for which the United States and the European Union disagree on essentiality.[69][70]
For U.S. food and dietary supplement labeling purposes the amount in a serving is expressed as a percent of Daily Value (%DV). For chromium labeling purposes 100% of the Daily Value was 120 μg, but as of May 27, 2016 it was revised to 35 μg to bring it into agreement with the RDA.[71] A table of the old and new adult Daily Values is provided at Reference Daily Intake. The original deadline to be in compliance was July 28, 2018, but on September 29, 2017 the FDA released a proposed rule that extended the deadline to January 1, 2020 for large companies and January 1, 2021 for small companies.[72]
Precautions

Main article: Chromium toxicity
Water-insoluble chromium(III) compounds and chromium metal are not considered a health hazard, while the toxicity and carcinogenic properties of chromium(VI) have been known for a long time.[73] Because of the specific transport mechanisms, only limited amounts of chromium(III) enter the cells. Several in vitro studies indicated that high concentrations of chromium(III) in the cell can lead to DNA damage.[74] Acute oral toxicity ranges between 1.5 and 3.3 mg/kg.[75] A 2008 review suggested that moderate uptake of chromium(III) through dietary supplements poses no genetic-toxic risk.[74] In the US, the Occupational Safety and Health Administration (OSHA) has designated a permissible exposure limit (PEL) in the workplace as a time-weighted average (TWA) of 1 mg/m3. The National Institute for Occupational Safety and Health (NIOSH) has set a recommended exposure limit (REL) of 0.5 mg/m3, time-weighted average. The IDLH (immediately dangerous to life and health) value is 250 mg/m3.[76]
Cr(VI)

The acute oral toxicity for chromium(VI) ranges between 50 and 150 mg/kg.[75] In the body, chromium(VI) is reduced by several mechanisms to chromium(III) already in the blood before it enters the cells. The chromium(III) is excreted from the body, whereas the chromate ion is transferred into the cell by a transport mechanism, by which also sulfate and phosphate ions enter the cell. The acute toxicity of chromium(VI) is due to its strong oxidational properties. After it reaches the blood stream, it damages the kidneys, the liver and blood cells through oxidation reactions. Hemolysis, renal, and liver failure result. Aggressive dialysis can be therapeutic.[77]
The carcinogenity of chromate dust has been known for a long time, and in 1890 the first publication described the elevated cancer risk of workers in a chromate dye company.[78][79] Three mechanisms have been proposed to describe the genotoxicity of chromium(VI). The first mechanism includes highly reactive hydroxyl radicals and other reactive radicals which are by products of the reduction of chromium(VI) to chromium(III). The second process includes the direct binding of chromium(V), produced by reduction in the cell, and chromium(IV) compounds to the DNA. The last mechanism attributed the genotoxicity to the binding to the DNA of the end product of the chromium(III) reduction.[80][81]
Chromium salts (chromates) are also the cause of allergic reactions in some people. Chromates are often used to manufacture, amongst other things, leather products, paints, cement, mortar and anti-corrosives. Contact with products containing chromates can lead to allergic contact dermatitis and irritant dermatitis, resulting in ulceration of the skin, sometimes referred to as "chrome ulcers". This condition is often found in workers that have been exposed to strong chromate solutions in electroplating, tanning and chrome-producing manufacturers.[82][83]
Environmental issues

Because chromium compounds were used in dyes, paints, and leather tanning compounds, these compounds are often found in soil and groundwater at abandoned industrial sites, now needing environmental cleanup and remediation. Primer paint containing hexavalent chromium is still widely used for aerospace and automobile refinishing applications.[84]
In 2010, the Environmental Working Group studied the drinking water in 35 American cities in the first nationwide study. The study found measurable hexavalent chromium in the tap water of 31 of the cities sampled, with Norman, Oklahoma, at the top of list; 25 cities had levels that exceeded California's proposed limit.[85]


#11
honeymik

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 myshyk, on 19 martie 2018 - 19:58, said:

Inseamna ca n-ai vazut/auzit  in viata ta de masina de trovalizat.
Corect, eu faceam referire la procesul de cromare prin metode relativ recente.

 myshyk, on 19 martie 2018 - 21:13, said:

Cat despre de ce nu se folosesc si la masini, sa stii ca o parte din elementele cromate ale masinilor, clantele spre exemplu se cromeaza cu aceast metoda.
Posted Image Se cromeaza prin procedeul descris de mine (trecerea prin mai multe cuve cu diferite substante.

 myshyk, on 19 martie 2018 - 21:13, said:

Mai exista si metode de cromare electrochimica in tambur, care e folosita tot la piese cu marime relativ mica.In rest, ornamentele mari si cele din table subtiri, trec prinm metoda calasica  a depunerilor electro-cnimice.
Cand vorbim de tambur de obicei este vorba de galvanizare, cu scop anticoroziv, nu decorativ.

#12
Jericho22

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T/C


Am refuzat..

#13
honeymik

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De ce? Puteai sa ne dai mai multe detalii ...

#14
Jericho22

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 honeymik, on 20 martie 2018 - 19:47, said:

De ce? Puteai sa ne dai mai multe detalii ...

Am auzit de la mai multe persoane ca e toxic. .Nu vreau sa risc. Poate acum la tinerete nu o sa se cunoasca dar vreau sa am o bătrânețe cu nepotii langa mine nu cu doctorii

Ps: Salariu era minim pe economie

Edited by Jericho22, 20 March 2018 - 20:28.


#15
honeymik

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 Jericho22, on 20 martie 2018 - 20:28, said:

Am auzit de la mai multe persoane ca ...
"Am auzit" nu este un motiv suficient de bun.

 Jericho22, on 20 martie 2018 - 20:28, said:

Ps: Salariu era minim pe economie
Asta da. Nici nu are rost sa acorzi mai mult interes job-ului.
Spor in continuare!

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