How to choose nickel rod N4 and N6| 5 working conditions +5 procurement traps

Published by Engineering Team, Shaanxi Qianyi Tuoda Technology Co., Ltd on 2026-07-23

The equipment supervisor of a chlor-alkali enterprise in Jiangsu Province encountered a difficult problem in selecting the nickel rod for the heating tube sheath of alkali evaporator, The drawing clearly requires N4 nickel rod to be suitable for high temperature concentrated alkali conditions greater than 315℃, However, some suppliers directly provide N6 nickel rod quotation, Each kilogram of material can save about 15 yuan.N6 carbon content index is higher, Graphitization embrittlement will occur under long-term high temperature service conditions, Seemingly lower procurement costs, If you choose the wrong material,, It can even cause the entire equipment to fail.

N6 is the two most widely used grades of industrial pure nickel rods, N4 belongs to ultra-low carbon and high purity nickel, N6 is commercially pure nickel.According to GB/T 5235‑2021 standard, the total content of N4 nickel + cobalt shall not be less than 99.9%, and carbon shall be controlled within 0.02%;N6 nickel + cobalt is not less than 99.5%, carbon upper limit 0.10%.The nominal purity difference between the two is only 0.5%, iron, copper, silicon, Manganese impurities control requirements N4 is also a lot stricter.Long-term operating conditions exceed 315℃, Carbon precipitates graphite at nickel grain boundaries, initiate embrittlement cracking, N4 avoids this risk by virtue of its extremely low carbon content.N4 corresponds to Ni201 UNS N02201 and N6 corresponds to Ni200 UNS N02200. ASTM B160 standard shall be implemented for bar testing.

Selection is mainly based on working temperature and medium conditions.Long-term heating conditions exceed 315℃, such as a high temperature concentrated caustic evaporator, Vacuum furnace tooling, cathode assembly for chlor-alkali electrolysis, N4 nickel rod is preferredthe temperature is in an alkali-resistant environment from normal temperature to 300 DEG C, N4 is better., N6 is selected as the evaluable operating condition under the limited budget conditionFor normal temperature conductive scenarios such as electroplating hangers and battery lugs, N6 can be selected;Food and medicine high soda washing equipment, in order to avoid impurity precipitation, it is recommended to use N4 nickel rod.If N6 is used incorrectly at high temperature, brittle fracture of parts may occur in a few months.

nickel rod mainstream diameter φ1‑200mm, Length support 1‑6 meters fixed length, The surface is divided into black skin, acid pickling, smooth sth. on a lathe, polish, square rod, Hexagonal rods support customization.Taking the smooth material of φ10‑50mm train as an example, N4 market refers to 195‑215 yuan/kg, N6 refers to 180‑205 yuan/kg, and the price difference is about 10‑15 yuan/kg;Large specification forging, zero cutting plus union will generate additional costs, N6 purchase volume of more than one ton can strive for batch discounts.The price difference per kilogram seems limited, However, the difference in the total price of large-volume purchases is obvious, The losses caused by equipment failure are far greater than the material price difference.

nickel rod unit price is high, brand appearance is difficult to distinguish, procurement should do three checks.The first check material quality certificate, focusing on confirming the total content of nickel and cobalt, carbon measured values;Secondly, XRF fluorescence spectrum detection is used, and the spectral peak signal of N4 impurities is lower;Third, check the product stamp, Regular product label, specification, welding by heat, Only pure nickel is marked without indicating the brand number of the furnace. It is necessary to be vigilant.

Common procurement risks in the industry need to pay attention to: recycling remelted raw materials posing as standard brands;N6 stamp N4 stamp for high temperature conditions;Ordering N4 at a high price and actually delivering N6;Cold drawing hard state material impersonates annealing state, processing hardness exceeds the standard;The purchase tolerance is not specified, and the arrival size cannot be assembled.The purchase contract must indicate the brand number, specification, surface states, size tolerance, At the same time, the warranty is required to provide nickel and cobalt, Carbon test data.

There are four difficulties in processing pure nickel rod: material sticking tool is easy to wrap chips, and sharp tool with large rake angle is needed to match sufficient coolant;Work hardening phenomenon is prominent, cutting needs to avoid hardened layer;Weak thermal conductivity, tip heat accumulation, strengthen cooling;ERNi‑1 pure nickel welding wire is used for welding, Argon arc welding on the back of argon protection, postweld annealing stress relief, And steel dissimilar welding to increase nickel-based transition layer.

Manufacturers rooted in Baoji China Titanium Valley can provide N4, N6 full specification pure nickel rod customization, Third-party spectrum test report can be issued, Traceability of batch records, engineer's binding medium, temperature, Force conditions to provide model selection reference.Full Analysis of Titanium Reactor Structure SelectionTitanium Heat Exchanger Selection Guidetitanium stirrerSelection and Procurement Guide

frequently asked questions

Q: How to choose N4 nickel rod and N6 nickel rod? A: long-term working temperature is greater than 315℃ high temperature concentrated alkali, vacuum furnace tooling selection N4;Normal temperature ‑300℃ alkali resistance, electroplating battery conductive scene, after evaluating the working conditions, select N6.

Q: What American standards do N4 and N4 nickel rods correspond to? A: N4 corresponds to Ni201 (UNS N02201) ultra-low carbon nickel, and N6 corresponds to Ni200 (UNS N02200) industrial pure nickel.

Q: How to avoid risks in nickel rod procurement? A: Check the nickel, cobalt and carbon content in the warranty;Check the batch number of the steel stamp furnace;Clarify surface condition and size tolerance, and conduct spectrum sampling if necessary.

disclaimer

This article selection ideas, Price range is based on industry project experience, For technical reference only, Not as engineering design, Direct basis for purchasing contract.The price of pure nickel raw material fluctuates with the electrolytic nickel market, Actual quotation is subject to market conditions on the day of order, The material selection suggestions for critical working conditions shall be comprehensively evaluated by professional technicians in combination with field working conditions and GB/T 5235‑2021 standards.