---
title: "Laser Cladding Process Control: Ni-Based Gear Steel Coatings"
url: https://www.intouchray.com/laser-cladding-process-control/
date: 2026-11-07
modified: 2026-11-07
lang: en
author: "Allan Hill"
description: "How the laser cladding process works on gear steel: powder choice, parameter effects on coating quality, and how Intouch cladding systems support parameter opti"
categories:
  - "Laser Cladding Machine"
tags:
  - "laser cladding equipment"
  - "laser cladding technology"
  - "Laser Cladding Test"
  - "Process Cladding"
image: https://www.intouchray.com/wp-content/uploads/2026/11/intouchray-6963a67f.jpg
word_count: 1721
---

# Laser Cladding Process Control: Ni-Based Gear Steel Coatings

# Process Control in Laser Cladding: Tuning Ni-Based Coatings on Gear Steel

A laser cladding process succeeds or fails on four variables: laser power, scanning speed, powder feed rate, and shielding gas flow. Get those four right on a gear steel such as 18CrNiMo7-6, and a Ni-based powder feed cladding layer will bond metallurgically, run dense, and hold hardness where the tooth surface needs it. Get them wrong, and the same coating comes off the machine with porosity and micro-cracks.

Gears earn their keep the hard way. High transmission efficiency, heavy bearing loads, long duty cycles — and every one of those loads lands on a tooth flank. Pitting, spalling, wear, plastic deformation, scuffing: these are the failure modes that end a gear set early. Surface modification is the practical counter, and laser metal deposition has two honest advantages over the alternatives — a short process cycle and a coating that fuses into the base metal rather than sitting on top of it. The catch is thermal. Melt pools cool violently fast, and that quench is exactly what invites pores and cracks. Parameter discipline is not optional.

This article walks through how a published single-factor study on 18CrNiMo7-6 gear steel approached that discipline, and what it means for anyone specifying a laser cladding system in production.

## Why Gear Steel, and Why Ni-Based Powder

![Laser Cladding Process Control: Ni-Based](https://www.intouchray.com/wp-content/uploads/2026/11/intouchray-fc81d853.jpg)

![Laser Cladding Process Control: Ni-Based](https://www.intouchray.com/wp-content/uploads/2026/11/intouchray-80705168.jpg)

Fe-, Ni- and Co-based alloys dominate laser hardfacing powder selection. Ni-based alloy powders keep winning the shortlist for three reasons: wear resistance, corrosion resistance, good wettability against steel — and a price that sits between tool-steel powders and cobalt grades. In procurement terms, moderate powder cost per kilogram against a coating that genuinely extends flank life is the trade that closes.

The base material in the referenced study is 18CrNiMo7-6, a carburized alloy structural steel under EN 10084 (its Chinese counterpart is 17Cr2Ni2Mo). After carburizing, quenching, low-temperature tempering and finishing, it carries the strength and impact properties demanded by wind-power gearboxes, port machinery, mine reducers and high-speed locomotive drives — exactly the sectors where a failed gear costs more than the repair.

**Composition of 18CrNiMo7-6 (mass fraction, %), per EN 10084:**

| C | Si | Mn | P | S | Cr | Ni | Mo | Al | V | Cu |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 0.15–0.20 | ≤0.40 | 0.50–0.90 | ≤0.02 | ≤0.02 | 1.50–1.80 | 1.40–1.70 | 0.25–0.35 | 0.02–0.04 | ≤0.05 | ≤0.30 |

## The Powder Recipe: NiCr20 Plus a Ceramic Assistant

The study used NiCr20 self-fluxing alloy powder — nickel balance with roughly 20% chromium, trace iron, silicon, aluminium and carbon. Self-fluxing behaviour matters on the floor: it wets cleanly, flows predictably through the feeder, and resists oxidation in the melt pool.

The interesting move is the second ingredient. ZrO2 ceramic powder, mixed in at a mass ratio of 48:1 against the NiCr20, acts as an assistant material. Zirconia brings thermal stability and phase-transformation toughening — under the thermal stress of cladding it absorbs strain that would otherwise open micro-cracks, raising coating density. Particle morphology was spherical in both powders, roughly 100 μm for NiCr20 and 50 μm for ZrO2, dried before use.

On the Intouchray floor, powder handling is where most first-time cladding jobs go wrong before the laser ever fires. Moisture in powder reads as porosity later; we treat drying and sieving as part of the process, not preparation for it.

## What a Cladding Setup Actually Consists Of

The test rig described in the research is a fair picture of any production laser cladding equipment line, ours included. Six components: cladding head, laser source, multi-axis motion (six-axis robot arm in the study), powder feeding system, water chiller, and control system.

The test unit ran a fiber source spanning 400–4000 W, a powder tray adjustable from 0 to 4 r/min handling 50–150 μm powder, and high-purity argon shielding the melt pool throughout. Water cooling holds the source and head at constant temperature — a detail that sounds mundane until a four-hour continuous job drifts thermally and the track geometry drifts with it.

For readers comparing machines rather than papers: Intouchray's IT-RF5018 cladding series covers the same architecture at production scale. The flatbed IT-RF 3000-12000 works a 500×300×400mm XYZ envelope with ±0.02mm repeatability; the robot version IT-RF5018-2 carries a 1.8 or 2.0 m arm on Fanuc, Kuka, Yaskawa or domestic platforms; the custom IT-RF5018-3 adds a positioner and ground rail rated to 5000 kg payload for large gear and roll work. Sources run 3–12 kW through a 600 μm core on QBH, delivering 0.5–2 mm cladding layers with round 4 mm or square 10–20 mm spots. That is the equipment context behind every number below.

## The Test Matrix: How Parameters Were Isolated

Single-factor testing is the blunt but honest way to isolate variables. The study clad single tracks about 20 mm long along the long side of plate specimens, varying one parameter at a time:

- Laser power: 500 / 700 / 900 W

- Scanning speed: 2 / 5 / 8 mm/s

- Powder feed rate: 8.8 / 11.1 / 13.2 g/min

- Held constant: argon at 4 L/min, φ4 mm spot, 250 mm defocus

Eleven runs (S1–S11), each repeated twice, is a small matrix by production standards but a clean read for trend direction.

| Run | Power (W) | Speed (mm/s) | Feed (g/min) |
| --- | --------- | ------------ | ------------ |
| S1 | 500 | 2 | 11.1 |
| S2 | 500 | 5 | 11.1 |
| S3 | 500 | 8 | 11.1 |
| S4 | 500 | 2 | 8.8 |
| S5 | 500 | 2 | 13.2 |
| S6 | 700 | 2 | 11.1 |
| S7 | 700 | 2 | 8.8 |
| S8 | 700 | 2 | 13.2 |
| S9 | 900 | 2 | 11.1 |
| S10 | 700 | 5 | 11.1 |
| S11 | 700 | 8 | 11.1 |

Evaluation followed standard metallographic practice: wire-cut 5 mm cubes, step-polish the cross-section, etch in aqua regia (HCl:HNO3 at 3:1, roughly 2 minutes), then optical and scanning microscopy. Vickers microhardness ran from 50 μm below the surface in 100 μm depth steps at 500 g load with 10 s dwell, three indents per depth, averaged — the repetition is what separates data from noise.

## What Each Parameter Does to the Coating

The study's findings, reported as trend directions, line up with what production experience predicts:

**Laser power up** → melt height, width and depth all increase. But dilution rises too, and the reported microstructure density and microhardness trend down at higher power. More heat is not more quality; it is more base-metal mixing and coarser grains.

**Scanning speed up** → track dimensions shrink across the board — height, width, depth. The reported microstructure gets less dense and hardness trends lower, because less energy per unit length means less complete fusion of the powder layer.

**Powder feed rate up** → this is the asymmetric one. Track height climbs steadily. Width rises then falls. Depth actually decreases — more powder absorbs energy, leaving less to melt the substrate. Meanwhile the reported density, refinement and microhardness all trend upward. Within the tested window, pushing powder feed was the move that improved coating quality rather than merely enlarging it.

We write this from the factory floor: when a customer's trial track looks fat but shallow and soft, the first thing we check is whether power was turned up when it should have been feed. The symptom is similar; the fix is opposite.

Taking macro morphology, microstructure and microhardness together as evaluation indexes, the study landed its optimum in the mid-band of the tested window — moderate power around the 700 W class paired with a raised powder feed — rather than at either extreme. We restate that as the study's reported conclusion, not as a universal recipe: your steel grade, spot size and powder lot will move it.

## Turning Research Trends into a Buyer's Checklist

If you are specifying a laser [cladding machine](https://www.intouchray.com/category/laser-cladding-machine/) or comparing laser cladding equipment suppliers, the study method translates directly into due diligence:

- **Demand the parameter matrix, not a single hero number.** A supplier quoting one power-and-speed combination has tested one coupon. Ask for the trend data.

- **Fix the constants in writing.** Spot diameter, defocus, argon flow, powder size band and drying state — the study held four variables constant to read three. Your qualification should do the same.

- **Repeat runs.** Two repeats per condition is the research minimum; for production qualification we prefer three, because a single good track proves nothing about drift.

- **Measure depth-wise hardness, not surface hardness.** The transition zone tells you whether dilution is controlled.

- **State the trade-off out loud.** Higher feed rates buy density and hardness but demand more laser power per gram to keep fusion complete — energy cost per square centimetre of coating goes up. On high-value gears, that premium pays; on commodity shafts, it may not.

One more practical note. ISO 11553 and IEC 60825-1 govern laser equipment safety classification, and EN 60204-1 covers electrical supply documentation on machines shipped into Europe — check certificates before comparing prices, because retrofitting compliance costs more than specifying it.

## FAQ

### Can laser cladding repair gear teeth directly?

Yes — this is one of its strongest applications. Robot-mounted heads (our IT-RF5018-2 runs Fanuc/Kuka arms) trace tooth profiles under CNC guidance, rebuilding flank material in 0.5–2 mm layers. A square or inner-welding head handles wide flanks and internal gear surfaces above 100 mm bore diameter.

### Why add ceramic powder to a metal alloy?

ZrO2 at small mass fractions toughens the coating through phase transformation and absorbs thermal stress, cutting micro-crack formation and raising density. It is a process aid, not a bulk alloying element.

### Does higher laser power always mean a better coating?

No. The study trends show density and hardness falling as power rises, because dilution and grain coarsening increase. Power must match powder feed and speed; mismatch in either direction costs quality.

### What tolerance should a cladding machine hold?

Repeatability around ±0.02 mm is achievable on a flatbed system — our IT-RF5018-1 is rated there by Intouchray's published data — and matters most for thin, uniform layers on precision gearing.

### Which industries drive this work hardest?

Wind power, port machinery, mining reducers and rail traction gears — the sectors specified on 18CrNiMo7-6 and similar carburized grades, where laser hardfacing extends service life on parts too large to replace cheaply.

Parameter optimization is patient work, but it is what separates a coating that lasts from one that fails its first inspection. If you are planning a cladding trial or comparing systems, send your material grade and part geometry to info@intouchray.com or visit www.intouchray.com — twenty-plus years of laser equipment manufacturing means we have likely run your case before.

**Related reading:** [laser applications by industry](https://www.intouchray.com/applications/) · [robotic laser cladding machines](https://www.intouchray.com/robotic-laser-cladding-machine/) · [laser cladding machines](https://www.intouchray.com/category/laser-cladding-machine/)